Loading...
1/* SPDX-License-Identifier: GPL-2.0 */
2/* Copyright (c) 2018 Facebook */
3
4#include <uapi/linux/btf.h>
5#include <uapi/linux/types.h>
6#include <linux/seq_file.h>
7#include <linux/compiler.h>
8#include <linux/ctype.h>
9#include <linux/errno.h>
10#include <linux/slab.h>
11#include <linux/anon_inodes.h>
12#include <linux/file.h>
13#include <linux/uaccess.h>
14#include <linux/kernel.h>
15#include <linux/idr.h>
16#include <linux/sort.h>
17#include <linux/bpf_verifier.h>
18#include <linux/btf.h>
19
20/* BTF (BPF Type Format) is the meta data format which describes
21 * the data types of BPF program/map. Hence, it basically focus
22 * on the C programming language which the modern BPF is primary
23 * using.
24 *
25 * ELF Section:
26 * ~~~~~~~~~~~
27 * The BTF data is stored under the ".BTF" ELF section
28 *
29 * struct btf_type:
30 * ~~~~~~~~~~~~~~~
31 * Each 'struct btf_type' object describes a C data type.
32 * Depending on the type it is describing, a 'struct btf_type'
33 * object may be followed by more data. F.e.
34 * To describe an array, 'struct btf_type' is followed by
35 * 'struct btf_array'.
36 *
37 * 'struct btf_type' and any extra data following it are
38 * 4 bytes aligned.
39 *
40 * Type section:
41 * ~~~~~~~~~~~~~
42 * The BTF type section contains a list of 'struct btf_type' objects.
43 * Each one describes a C type. Recall from the above section
44 * that a 'struct btf_type' object could be immediately followed by extra
45 * data in order to desribe some particular C types.
46 *
47 * type_id:
48 * ~~~~~~~
49 * Each btf_type object is identified by a type_id. The type_id
50 * is implicitly implied by the location of the btf_type object in
51 * the BTF type section. The first one has type_id 1. The second
52 * one has type_id 2...etc. Hence, an earlier btf_type has
53 * a smaller type_id.
54 *
55 * A btf_type object may refer to another btf_type object by using
56 * type_id (i.e. the "type" in the "struct btf_type").
57 *
58 * NOTE that we cannot assume any reference-order.
59 * A btf_type object can refer to an earlier btf_type object
60 * but it can also refer to a later btf_type object.
61 *
62 * For example, to describe "const void *". A btf_type
63 * object describing "const" may refer to another btf_type
64 * object describing "void *". This type-reference is done
65 * by specifying type_id:
66 *
67 * [1] CONST (anon) type_id=2
68 * [2] PTR (anon) type_id=0
69 *
70 * The above is the btf_verifier debug log:
71 * - Each line started with "[?]" is a btf_type object
72 * - [?] is the type_id of the btf_type object.
73 * - CONST/PTR is the BTF_KIND_XXX
74 * - "(anon)" is the name of the type. It just
75 * happens that CONST and PTR has no name.
76 * - type_id=XXX is the 'u32 type' in btf_type
77 *
78 * NOTE: "void" has type_id 0
79 *
80 * String section:
81 * ~~~~~~~~~~~~~~
82 * The BTF string section contains the names used by the type section.
83 * Each string is referred by an "offset" from the beginning of the
84 * string section.
85 *
86 * Each string is '\0' terminated.
87 *
88 * The first character in the string section must be '\0'
89 * which is used to mean 'anonymous'. Some btf_type may not
90 * have a name.
91 */
92
93/* BTF verification:
94 *
95 * To verify BTF data, two passes are needed.
96 *
97 * Pass #1
98 * ~~~~~~~
99 * The first pass is to collect all btf_type objects to
100 * an array: "btf->types".
101 *
102 * Depending on the C type that a btf_type is describing,
103 * a btf_type may be followed by extra data. We don't know
104 * how many btf_type is there, and more importantly we don't
105 * know where each btf_type is located in the type section.
106 *
107 * Without knowing the location of each type_id, most verifications
108 * cannot be done. e.g. an earlier btf_type may refer to a later
109 * btf_type (recall the "const void *" above), so we cannot
110 * check this type-reference in the first pass.
111 *
112 * In the first pass, it still does some verifications (e.g.
113 * checking the name is a valid offset to the string section).
114 *
115 * Pass #2
116 * ~~~~~~~
117 * The main focus is to resolve a btf_type that is referring
118 * to another type.
119 *
120 * We have to ensure the referring type:
121 * 1) does exist in the BTF (i.e. in btf->types[])
122 * 2) does not cause a loop:
123 * struct A {
124 * struct B b;
125 * };
126 *
127 * struct B {
128 * struct A a;
129 * };
130 *
131 * btf_type_needs_resolve() decides if a btf_type needs
132 * to be resolved.
133 *
134 * The needs_resolve type implements the "resolve()" ops which
135 * essentially does a DFS and detects backedge.
136 *
137 * During resolve (or DFS), different C types have different
138 * "RESOLVED" conditions.
139 *
140 * When resolving a BTF_KIND_STRUCT, we need to resolve all its
141 * members because a member is always referring to another
142 * type. A struct's member can be treated as "RESOLVED" if
143 * it is referring to a BTF_KIND_PTR. Otherwise, the
144 * following valid C struct would be rejected:
145 *
146 * struct A {
147 * int m;
148 * struct A *a;
149 * };
150 *
151 * When resolving a BTF_KIND_PTR, it needs to keep resolving if
152 * it is referring to another BTF_KIND_PTR. Otherwise, we cannot
153 * detect a pointer loop, e.g.:
154 * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR +
155 * ^ |
156 * +-----------------------------------------+
157 *
158 */
159
160#define BITS_PER_U128 (sizeof(u64) * BITS_PER_BYTE * 2)
161#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
162#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
163#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
164#define BITS_ROUNDUP_BYTES(bits) \
165 (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
166
167#define BTF_INFO_MASK 0x8f00ffff
168#define BTF_INT_MASK 0x0fffffff
169#define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
170#define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
171
172/* 16MB for 64k structs and each has 16 members and
173 * a few MB spaces for the string section.
174 * The hard limit is S32_MAX.
175 */
176#define BTF_MAX_SIZE (16 * 1024 * 1024)
177
178#define for_each_member(i, struct_type, member) \
179 for (i = 0, member = btf_type_member(struct_type); \
180 i < btf_type_vlen(struct_type); \
181 i++, member++)
182
183#define for_each_member_from(i, from, struct_type, member) \
184 for (i = from, member = btf_type_member(struct_type) + from; \
185 i < btf_type_vlen(struct_type); \
186 i++, member++)
187
188#define for_each_vsi(i, struct_type, member) \
189 for (i = 0, member = btf_type_var_secinfo(struct_type); \
190 i < btf_type_vlen(struct_type); \
191 i++, member++)
192
193#define for_each_vsi_from(i, from, struct_type, member) \
194 for (i = from, member = btf_type_var_secinfo(struct_type) + from; \
195 i < btf_type_vlen(struct_type); \
196 i++, member++)
197
198DEFINE_IDR(btf_idr);
199DEFINE_SPINLOCK(btf_idr_lock);
200
201struct btf {
202 void *data;
203 struct btf_type **types;
204 u32 *resolved_ids;
205 u32 *resolved_sizes;
206 const char *strings;
207 void *nohdr_data;
208 struct btf_header hdr;
209 u32 nr_types;
210 u32 types_size;
211 u32 data_size;
212 refcount_t refcnt;
213 u32 id;
214 struct rcu_head rcu;
215};
216
217enum verifier_phase {
218 CHECK_META,
219 CHECK_TYPE,
220};
221
222struct resolve_vertex {
223 const struct btf_type *t;
224 u32 type_id;
225 u16 next_member;
226};
227
228enum visit_state {
229 NOT_VISITED,
230 VISITED,
231 RESOLVED,
232};
233
234enum resolve_mode {
235 RESOLVE_TBD, /* To Be Determined */
236 RESOLVE_PTR, /* Resolving for Pointer */
237 RESOLVE_STRUCT_OR_ARRAY, /* Resolving for struct/union
238 * or array
239 */
240};
241
242#define MAX_RESOLVE_DEPTH 32
243
244struct btf_sec_info {
245 u32 off;
246 u32 len;
247};
248
249struct btf_verifier_env {
250 struct btf *btf;
251 u8 *visit_states;
252 struct resolve_vertex stack[MAX_RESOLVE_DEPTH];
253 struct bpf_verifier_log log;
254 u32 log_type_id;
255 u32 top_stack;
256 enum verifier_phase phase;
257 enum resolve_mode resolve_mode;
258};
259
260static const char * const btf_kind_str[NR_BTF_KINDS] = {
261 [BTF_KIND_UNKN] = "UNKNOWN",
262 [BTF_KIND_INT] = "INT",
263 [BTF_KIND_PTR] = "PTR",
264 [BTF_KIND_ARRAY] = "ARRAY",
265 [BTF_KIND_STRUCT] = "STRUCT",
266 [BTF_KIND_UNION] = "UNION",
267 [BTF_KIND_ENUM] = "ENUM",
268 [BTF_KIND_FWD] = "FWD",
269 [BTF_KIND_TYPEDEF] = "TYPEDEF",
270 [BTF_KIND_VOLATILE] = "VOLATILE",
271 [BTF_KIND_CONST] = "CONST",
272 [BTF_KIND_RESTRICT] = "RESTRICT",
273 [BTF_KIND_FUNC] = "FUNC",
274 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
275 [BTF_KIND_VAR] = "VAR",
276 [BTF_KIND_DATASEC] = "DATASEC",
277};
278
279struct btf_kind_operations {
280 s32 (*check_meta)(struct btf_verifier_env *env,
281 const struct btf_type *t,
282 u32 meta_left);
283 int (*resolve)(struct btf_verifier_env *env,
284 const struct resolve_vertex *v);
285 int (*check_member)(struct btf_verifier_env *env,
286 const struct btf_type *struct_type,
287 const struct btf_member *member,
288 const struct btf_type *member_type);
289 int (*check_kflag_member)(struct btf_verifier_env *env,
290 const struct btf_type *struct_type,
291 const struct btf_member *member,
292 const struct btf_type *member_type);
293 void (*log_details)(struct btf_verifier_env *env,
294 const struct btf_type *t);
295 void (*seq_show)(const struct btf *btf, const struct btf_type *t,
296 u32 type_id, void *data, u8 bits_offsets,
297 struct seq_file *m);
298};
299
300static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS];
301static struct btf_type btf_void;
302
303static int btf_resolve(struct btf_verifier_env *env,
304 const struct btf_type *t, u32 type_id);
305
306static bool btf_type_is_modifier(const struct btf_type *t)
307{
308 /* Some of them is not strictly a C modifier
309 * but they are grouped into the same bucket
310 * for BTF concern:
311 * A type (t) that refers to another
312 * type through t->type AND its size cannot
313 * be determined without following the t->type.
314 *
315 * ptr does not fall into this bucket
316 * because its size is always sizeof(void *).
317 */
318 switch (BTF_INFO_KIND(t->info)) {
319 case BTF_KIND_TYPEDEF:
320 case BTF_KIND_VOLATILE:
321 case BTF_KIND_CONST:
322 case BTF_KIND_RESTRICT:
323 return true;
324 }
325
326 return false;
327}
328
329bool btf_type_is_void(const struct btf_type *t)
330{
331 return t == &btf_void;
332}
333
334static bool btf_type_is_fwd(const struct btf_type *t)
335{
336 return BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
337}
338
339static bool btf_type_is_func(const struct btf_type *t)
340{
341 return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC;
342}
343
344static bool btf_type_is_func_proto(const struct btf_type *t)
345{
346 return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC_PROTO;
347}
348
349static bool btf_type_nosize(const struct btf_type *t)
350{
351 return btf_type_is_void(t) || btf_type_is_fwd(t) ||
352 btf_type_is_func(t) || btf_type_is_func_proto(t);
353}
354
355static bool btf_type_nosize_or_null(const struct btf_type *t)
356{
357 return !t || btf_type_nosize(t);
358}
359
360/* union is only a special case of struct:
361 * all its offsetof(member) == 0
362 */
363static bool btf_type_is_struct(const struct btf_type *t)
364{
365 u8 kind = BTF_INFO_KIND(t->info);
366
367 return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
368}
369
370static bool __btf_type_is_struct(const struct btf_type *t)
371{
372 return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT;
373}
374
375static bool btf_type_is_array(const struct btf_type *t)
376{
377 return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY;
378}
379
380static bool btf_type_is_ptr(const struct btf_type *t)
381{
382 return BTF_INFO_KIND(t->info) == BTF_KIND_PTR;
383}
384
385static bool btf_type_is_int(const struct btf_type *t)
386{
387 return BTF_INFO_KIND(t->info) == BTF_KIND_INT;
388}
389
390static bool btf_type_is_var(const struct btf_type *t)
391{
392 return BTF_INFO_KIND(t->info) == BTF_KIND_VAR;
393}
394
395static bool btf_type_is_datasec(const struct btf_type *t)
396{
397 return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
398}
399
400/* Types that act only as a source, not sink or intermediate
401 * type when resolving.
402 */
403static bool btf_type_is_resolve_source_only(const struct btf_type *t)
404{
405 return btf_type_is_var(t) ||
406 btf_type_is_datasec(t);
407}
408
409/* What types need to be resolved?
410 *
411 * btf_type_is_modifier() is an obvious one.
412 *
413 * btf_type_is_struct() because its member refers to
414 * another type (through member->type).
415 *
416 * btf_type_is_var() because the variable refers to
417 * another type. btf_type_is_datasec() holds multiple
418 * btf_type_is_var() types that need resolving.
419 *
420 * btf_type_is_array() because its element (array->type)
421 * refers to another type. Array can be thought of a
422 * special case of struct while array just has the same
423 * member-type repeated by array->nelems of times.
424 */
425static bool btf_type_needs_resolve(const struct btf_type *t)
426{
427 return btf_type_is_modifier(t) ||
428 btf_type_is_ptr(t) ||
429 btf_type_is_struct(t) ||
430 btf_type_is_array(t) ||
431 btf_type_is_var(t) ||
432 btf_type_is_datasec(t);
433}
434
435/* t->size can be used */
436static bool btf_type_has_size(const struct btf_type *t)
437{
438 switch (BTF_INFO_KIND(t->info)) {
439 case BTF_KIND_INT:
440 case BTF_KIND_STRUCT:
441 case BTF_KIND_UNION:
442 case BTF_KIND_ENUM:
443 case BTF_KIND_DATASEC:
444 return true;
445 }
446
447 return false;
448}
449
450static const char *btf_int_encoding_str(u8 encoding)
451{
452 if (encoding == 0)
453 return "(none)";
454 else if (encoding == BTF_INT_SIGNED)
455 return "SIGNED";
456 else if (encoding == BTF_INT_CHAR)
457 return "CHAR";
458 else if (encoding == BTF_INT_BOOL)
459 return "BOOL";
460 else
461 return "UNKN";
462}
463
464static u16 btf_type_vlen(const struct btf_type *t)
465{
466 return BTF_INFO_VLEN(t->info);
467}
468
469static bool btf_type_kflag(const struct btf_type *t)
470{
471 return BTF_INFO_KFLAG(t->info);
472}
473
474static u32 btf_member_bit_offset(const struct btf_type *struct_type,
475 const struct btf_member *member)
476{
477 return btf_type_kflag(struct_type) ? BTF_MEMBER_BIT_OFFSET(member->offset)
478 : member->offset;
479}
480
481static u32 btf_member_bitfield_size(const struct btf_type *struct_type,
482 const struct btf_member *member)
483{
484 return btf_type_kflag(struct_type) ? BTF_MEMBER_BITFIELD_SIZE(member->offset)
485 : 0;
486}
487
488static u32 btf_type_int(const struct btf_type *t)
489{
490 return *(u32 *)(t + 1);
491}
492
493static const struct btf_array *btf_type_array(const struct btf_type *t)
494{
495 return (const struct btf_array *)(t + 1);
496}
497
498static const struct btf_member *btf_type_member(const struct btf_type *t)
499{
500 return (const struct btf_member *)(t + 1);
501}
502
503static const struct btf_enum *btf_type_enum(const struct btf_type *t)
504{
505 return (const struct btf_enum *)(t + 1);
506}
507
508static const struct btf_var *btf_type_var(const struct btf_type *t)
509{
510 return (const struct btf_var *)(t + 1);
511}
512
513static const struct btf_var_secinfo *btf_type_var_secinfo(const struct btf_type *t)
514{
515 return (const struct btf_var_secinfo *)(t + 1);
516}
517
518static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
519{
520 return kind_ops[BTF_INFO_KIND(t->info)];
521}
522
523static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
524{
525 return BTF_STR_OFFSET_VALID(offset) &&
526 offset < btf->hdr.str_len;
527}
528
529static bool __btf_name_char_ok(char c, bool first, bool dot_ok)
530{
531 if ((first ? !isalpha(c) :
532 !isalnum(c)) &&
533 c != '_' &&
534 ((c == '.' && !dot_ok) ||
535 c != '.'))
536 return false;
537 return true;
538}
539
540static bool __btf_name_valid(const struct btf *btf, u32 offset, bool dot_ok)
541{
542 /* offset must be valid */
543 const char *src = &btf->strings[offset];
544 const char *src_limit;
545
546 if (!__btf_name_char_ok(*src, true, dot_ok))
547 return false;
548
549 /* set a limit on identifier length */
550 src_limit = src + KSYM_NAME_LEN;
551 src++;
552 while (*src && src < src_limit) {
553 if (!__btf_name_char_ok(*src, false, dot_ok))
554 return false;
555 src++;
556 }
557
558 return !*src;
559}
560
561/* Only C-style identifier is permitted. This can be relaxed if
562 * necessary.
563 */
564static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
565{
566 return __btf_name_valid(btf, offset, false);
567}
568
569static bool btf_name_valid_section(const struct btf *btf, u32 offset)
570{
571 return __btf_name_valid(btf, offset, true);
572}
573
574static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
575{
576 if (!offset)
577 return "(anon)";
578 else if (offset < btf->hdr.str_len)
579 return &btf->strings[offset];
580 else
581 return "(invalid-name-offset)";
582}
583
584const char *btf_name_by_offset(const struct btf *btf, u32 offset)
585{
586 if (offset < btf->hdr.str_len)
587 return &btf->strings[offset];
588
589 return NULL;
590}
591
592const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
593{
594 if (type_id > btf->nr_types)
595 return NULL;
596
597 return btf->types[type_id];
598}
599
600/*
601 * Regular int is not a bit field and it must be either
602 * u8/u16/u32/u64 or __int128.
603 */
604static bool btf_type_int_is_regular(const struct btf_type *t)
605{
606 u8 nr_bits, nr_bytes;
607 u32 int_data;
608
609 int_data = btf_type_int(t);
610 nr_bits = BTF_INT_BITS(int_data);
611 nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
612 if (BITS_PER_BYTE_MASKED(nr_bits) ||
613 BTF_INT_OFFSET(int_data) ||
614 (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) &&
615 nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64) &&
616 nr_bytes != (2 * sizeof(u64)))) {
617 return false;
618 }
619
620 return true;
621}
622
623/*
624 * Check that given struct member is a regular int with expected
625 * offset and size.
626 */
627bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
628 const struct btf_member *m,
629 u32 expected_offset, u32 expected_size)
630{
631 const struct btf_type *t;
632 u32 id, int_data;
633 u8 nr_bits;
634
635 id = m->type;
636 t = btf_type_id_size(btf, &id, NULL);
637 if (!t || !btf_type_is_int(t))
638 return false;
639
640 int_data = btf_type_int(t);
641 nr_bits = BTF_INT_BITS(int_data);
642 if (btf_type_kflag(s)) {
643 u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset);
644 u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset);
645
646 /* if kflag set, int should be a regular int and
647 * bit offset should be at byte boundary.
648 */
649 return !bitfield_size &&
650 BITS_ROUNDUP_BYTES(bit_offset) == expected_offset &&
651 BITS_ROUNDUP_BYTES(nr_bits) == expected_size;
652 }
653
654 if (BTF_INT_OFFSET(int_data) ||
655 BITS_PER_BYTE_MASKED(m->offset) ||
656 BITS_ROUNDUP_BYTES(m->offset) != expected_offset ||
657 BITS_PER_BYTE_MASKED(nr_bits) ||
658 BITS_ROUNDUP_BYTES(nr_bits) != expected_size)
659 return false;
660
661 return true;
662}
663
664__printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
665 const char *fmt, ...)
666{
667 va_list args;
668
669 va_start(args, fmt);
670 bpf_verifier_vlog(log, fmt, args);
671 va_end(args);
672}
673
674__printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
675 const char *fmt, ...)
676{
677 struct bpf_verifier_log *log = &env->log;
678 va_list args;
679
680 if (!bpf_verifier_log_needed(log))
681 return;
682
683 va_start(args, fmt);
684 bpf_verifier_vlog(log, fmt, args);
685 va_end(args);
686}
687
688__printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
689 const struct btf_type *t,
690 bool log_details,
691 const char *fmt, ...)
692{
693 struct bpf_verifier_log *log = &env->log;
694 u8 kind = BTF_INFO_KIND(t->info);
695 struct btf *btf = env->btf;
696 va_list args;
697
698 if (!bpf_verifier_log_needed(log))
699 return;
700
701 __btf_verifier_log(log, "[%u] %s %s%s",
702 env->log_type_id,
703 btf_kind_str[kind],
704 __btf_name_by_offset(btf, t->name_off),
705 log_details ? " " : "");
706
707 if (log_details)
708 btf_type_ops(t)->log_details(env, t);
709
710 if (fmt && *fmt) {
711 __btf_verifier_log(log, " ");
712 va_start(args, fmt);
713 bpf_verifier_vlog(log, fmt, args);
714 va_end(args);
715 }
716
717 __btf_verifier_log(log, "\n");
718}
719
720#define btf_verifier_log_type(env, t, ...) \
721 __btf_verifier_log_type((env), (t), true, __VA_ARGS__)
722#define btf_verifier_log_basic(env, t, ...) \
723 __btf_verifier_log_type((env), (t), false, __VA_ARGS__)
724
725__printf(4, 5)
726static void btf_verifier_log_member(struct btf_verifier_env *env,
727 const struct btf_type *struct_type,
728 const struct btf_member *member,
729 const char *fmt, ...)
730{
731 struct bpf_verifier_log *log = &env->log;
732 struct btf *btf = env->btf;
733 va_list args;
734
735 if (!bpf_verifier_log_needed(log))
736 return;
737
738 /* The CHECK_META phase already did a btf dump.
739 *
740 * If member is logged again, it must hit an error in
741 * parsing this member. It is useful to print out which
742 * struct this member belongs to.
743 */
744 if (env->phase != CHECK_META)
745 btf_verifier_log_type(env, struct_type, NULL);
746
747 if (btf_type_kflag(struct_type))
748 __btf_verifier_log(log,
749 "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
750 __btf_name_by_offset(btf, member->name_off),
751 member->type,
752 BTF_MEMBER_BITFIELD_SIZE(member->offset),
753 BTF_MEMBER_BIT_OFFSET(member->offset));
754 else
755 __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
756 __btf_name_by_offset(btf, member->name_off),
757 member->type, member->offset);
758
759 if (fmt && *fmt) {
760 __btf_verifier_log(log, " ");
761 va_start(args, fmt);
762 bpf_verifier_vlog(log, fmt, args);
763 va_end(args);
764 }
765
766 __btf_verifier_log(log, "\n");
767}
768
769__printf(4, 5)
770static void btf_verifier_log_vsi(struct btf_verifier_env *env,
771 const struct btf_type *datasec_type,
772 const struct btf_var_secinfo *vsi,
773 const char *fmt, ...)
774{
775 struct bpf_verifier_log *log = &env->log;
776 va_list args;
777
778 if (!bpf_verifier_log_needed(log))
779 return;
780 if (env->phase != CHECK_META)
781 btf_verifier_log_type(env, datasec_type, NULL);
782
783 __btf_verifier_log(log, "\t type_id=%u offset=%u size=%u",
784 vsi->type, vsi->offset, vsi->size);
785 if (fmt && *fmt) {
786 __btf_verifier_log(log, " ");
787 va_start(args, fmt);
788 bpf_verifier_vlog(log, fmt, args);
789 va_end(args);
790 }
791
792 __btf_verifier_log(log, "\n");
793}
794
795static void btf_verifier_log_hdr(struct btf_verifier_env *env,
796 u32 btf_data_size)
797{
798 struct bpf_verifier_log *log = &env->log;
799 const struct btf *btf = env->btf;
800 const struct btf_header *hdr;
801
802 if (!bpf_verifier_log_needed(log))
803 return;
804
805 hdr = &btf->hdr;
806 __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
807 __btf_verifier_log(log, "version: %u\n", hdr->version);
808 __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
809 __btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
810 __btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
811 __btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
812 __btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
813 __btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
814 __btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
815}
816
817static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
818{
819 struct btf *btf = env->btf;
820
821 /* < 2 because +1 for btf_void which is always in btf->types[0].
822 * btf_void is not accounted in btf->nr_types because btf_void
823 * does not come from the BTF file.
824 */
825 if (btf->types_size - btf->nr_types < 2) {
826 /* Expand 'types' array */
827
828 struct btf_type **new_types;
829 u32 expand_by, new_size;
830
831 if (btf->types_size == BTF_MAX_TYPE) {
832 btf_verifier_log(env, "Exceeded max num of types");
833 return -E2BIG;
834 }
835
836 expand_by = max_t(u32, btf->types_size >> 2, 16);
837 new_size = min_t(u32, BTF_MAX_TYPE,
838 btf->types_size + expand_by);
839
840 new_types = kvcalloc(new_size, sizeof(*new_types),
841 GFP_KERNEL | __GFP_NOWARN);
842 if (!new_types)
843 return -ENOMEM;
844
845 if (btf->nr_types == 0)
846 new_types[0] = &btf_void;
847 else
848 memcpy(new_types, btf->types,
849 sizeof(*btf->types) * (btf->nr_types + 1));
850
851 kvfree(btf->types);
852 btf->types = new_types;
853 btf->types_size = new_size;
854 }
855
856 btf->types[++(btf->nr_types)] = t;
857
858 return 0;
859}
860
861static int btf_alloc_id(struct btf *btf)
862{
863 int id;
864
865 idr_preload(GFP_KERNEL);
866 spin_lock_bh(&btf_idr_lock);
867 id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
868 if (id > 0)
869 btf->id = id;
870 spin_unlock_bh(&btf_idr_lock);
871 idr_preload_end();
872
873 if (WARN_ON_ONCE(!id))
874 return -ENOSPC;
875
876 return id > 0 ? 0 : id;
877}
878
879static void btf_free_id(struct btf *btf)
880{
881 unsigned long flags;
882
883 /*
884 * In map-in-map, calling map_delete_elem() on outer
885 * map will call bpf_map_put on the inner map.
886 * It will then eventually call btf_free_id()
887 * on the inner map. Some of the map_delete_elem()
888 * implementation may have irq disabled, so
889 * we need to use the _irqsave() version instead
890 * of the _bh() version.
891 */
892 spin_lock_irqsave(&btf_idr_lock, flags);
893 idr_remove(&btf_idr, btf->id);
894 spin_unlock_irqrestore(&btf_idr_lock, flags);
895}
896
897static void btf_free(struct btf *btf)
898{
899 kvfree(btf->types);
900 kvfree(btf->resolved_sizes);
901 kvfree(btf->resolved_ids);
902 kvfree(btf->data);
903 kfree(btf);
904}
905
906static void btf_free_rcu(struct rcu_head *rcu)
907{
908 struct btf *btf = container_of(rcu, struct btf, rcu);
909
910 btf_free(btf);
911}
912
913void btf_put(struct btf *btf)
914{
915 if (btf && refcount_dec_and_test(&btf->refcnt)) {
916 btf_free_id(btf);
917 call_rcu(&btf->rcu, btf_free_rcu);
918 }
919}
920
921static int env_resolve_init(struct btf_verifier_env *env)
922{
923 struct btf *btf = env->btf;
924 u32 nr_types = btf->nr_types;
925 u32 *resolved_sizes = NULL;
926 u32 *resolved_ids = NULL;
927 u8 *visit_states = NULL;
928
929 /* +1 for btf_void */
930 resolved_sizes = kvcalloc(nr_types + 1, sizeof(*resolved_sizes),
931 GFP_KERNEL | __GFP_NOWARN);
932 if (!resolved_sizes)
933 goto nomem;
934
935 resolved_ids = kvcalloc(nr_types + 1, sizeof(*resolved_ids),
936 GFP_KERNEL | __GFP_NOWARN);
937 if (!resolved_ids)
938 goto nomem;
939
940 visit_states = kvcalloc(nr_types + 1, sizeof(*visit_states),
941 GFP_KERNEL | __GFP_NOWARN);
942 if (!visit_states)
943 goto nomem;
944
945 btf->resolved_sizes = resolved_sizes;
946 btf->resolved_ids = resolved_ids;
947 env->visit_states = visit_states;
948
949 return 0;
950
951nomem:
952 kvfree(resolved_sizes);
953 kvfree(resolved_ids);
954 kvfree(visit_states);
955 return -ENOMEM;
956}
957
958static void btf_verifier_env_free(struct btf_verifier_env *env)
959{
960 kvfree(env->visit_states);
961 kfree(env);
962}
963
964static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
965 const struct btf_type *next_type)
966{
967 switch (env->resolve_mode) {
968 case RESOLVE_TBD:
969 /* int, enum or void is a sink */
970 return !btf_type_needs_resolve(next_type);
971 case RESOLVE_PTR:
972 /* int, enum, void, struct, array, func or func_proto is a sink
973 * for ptr
974 */
975 return !btf_type_is_modifier(next_type) &&
976 !btf_type_is_ptr(next_type);
977 case RESOLVE_STRUCT_OR_ARRAY:
978 /* int, enum, void, ptr, func or func_proto is a sink
979 * for struct and array
980 */
981 return !btf_type_is_modifier(next_type) &&
982 !btf_type_is_array(next_type) &&
983 !btf_type_is_struct(next_type);
984 default:
985 BUG();
986 }
987}
988
989static bool env_type_is_resolved(const struct btf_verifier_env *env,
990 u32 type_id)
991{
992 return env->visit_states[type_id] == RESOLVED;
993}
994
995static int env_stack_push(struct btf_verifier_env *env,
996 const struct btf_type *t, u32 type_id)
997{
998 struct resolve_vertex *v;
999
1000 if (env->top_stack == MAX_RESOLVE_DEPTH)
1001 return -E2BIG;
1002
1003 if (env->visit_states[type_id] != NOT_VISITED)
1004 return -EEXIST;
1005
1006 env->visit_states[type_id] = VISITED;
1007
1008 v = &env->stack[env->top_stack++];
1009 v->t = t;
1010 v->type_id = type_id;
1011 v->next_member = 0;
1012
1013 if (env->resolve_mode == RESOLVE_TBD) {
1014 if (btf_type_is_ptr(t))
1015 env->resolve_mode = RESOLVE_PTR;
1016 else if (btf_type_is_struct(t) || btf_type_is_array(t))
1017 env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
1018 }
1019
1020 return 0;
1021}
1022
1023static void env_stack_set_next_member(struct btf_verifier_env *env,
1024 u16 next_member)
1025{
1026 env->stack[env->top_stack - 1].next_member = next_member;
1027}
1028
1029static void env_stack_pop_resolved(struct btf_verifier_env *env,
1030 u32 resolved_type_id,
1031 u32 resolved_size)
1032{
1033 u32 type_id = env->stack[--(env->top_stack)].type_id;
1034 struct btf *btf = env->btf;
1035
1036 btf->resolved_sizes[type_id] = resolved_size;
1037 btf->resolved_ids[type_id] = resolved_type_id;
1038 env->visit_states[type_id] = RESOLVED;
1039}
1040
1041static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
1042{
1043 return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
1044}
1045
1046/* The input param "type_id" must point to a needs_resolve type */
1047static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
1048 u32 *type_id)
1049{
1050 *type_id = btf->resolved_ids[*type_id];
1051 return btf_type_by_id(btf, *type_id);
1052}
1053
1054const struct btf_type *btf_type_id_size(const struct btf *btf,
1055 u32 *type_id, u32 *ret_size)
1056{
1057 const struct btf_type *size_type;
1058 u32 size_type_id = *type_id;
1059 u32 size = 0;
1060
1061 size_type = btf_type_by_id(btf, size_type_id);
1062 if (btf_type_nosize_or_null(size_type))
1063 return NULL;
1064
1065 if (btf_type_has_size(size_type)) {
1066 size = size_type->size;
1067 } else if (btf_type_is_array(size_type)) {
1068 size = btf->resolved_sizes[size_type_id];
1069 } else if (btf_type_is_ptr(size_type)) {
1070 size = sizeof(void *);
1071 } else {
1072 if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) &&
1073 !btf_type_is_var(size_type)))
1074 return NULL;
1075
1076 size_type_id = btf->resolved_ids[size_type_id];
1077 size_type = btf_type_by_id(btf, size_type_id);
1078 if (btf_type_nosize_or_null(size_type))
1079 return NULL;
1080 else if (btf_type_has_size(size_type))
1081 size = size_type->size;
1082 else if (btf_type_is_array(size_type))
1083 size = btf->resolved_sizes[size_type_id];
1084 else if (btf_type_is_ptr(size_type))
1085 size = sizeof(void *);
1086 else
1087 return NULL;
1088 }
1089
1090 *type_id = size_type_id;
1091 if (ret_size)
1092 *ret_size = size;
1093
1094 return size_type;
1095}
1096
1097static int btf_df_check_member(struct btf_verifier_env *env,
1098 const struct btf_type *struct_type,
1099 const struct btf_member *member,
1100 const struct btf_type *member_type)
1101{
1102 btf_verifier_log_basic(env, struct_type,
1103 "Unsupported check_member");
1104 return -EINVAL;
1105}
1106
1107static int btf_df_check_kflag_member(struct btf_verifier_env *env,
1108 const struct btf_type *struct_type,
1109 const struct btf_member *member,
1110 const struct btf_type *member_type)
1111{
1112 btf_verifier_log_basic(env, struct_type,
1113 "Unsupported check_kflag_member");
1114 return -EINVAL;
1115}
1116
1117/* Used for ptr, array and struct/union type members.
1118 * int, enum and modifier types have their specific callback functions.
1119 */
1120static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
1121 const struct btf_type *struct_type,
1122 const struct btf_member *member,
1123 const struct btf_type *member_type)
1124{
1125 if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) {
1126 btf_verifier_log_member(env, struct_type, member,
1127 "Invalid member bitfield_size");
1128 return -EINVAL;
1129 }
1130
1131 /* bitfield size is 0, so member->offset represents bit offset only.
1132 * It is safe to call non kflag check_member variants.
1133 */
1134 return btf_type_ops(member_type)->check_member(env, struct_type,
1135 member,
1136 member_type);
1137}
1138
1139static int btf_df_resolve(struct btf_verifier_env *env,
1140 const struct resolve_vertex *v)
1141{
1142 btf_verifier_log_basic(env, v->t, "Unsupported resolve");
1143 return -EINVAL;
1144}
1145
1146static void btf_df_seq_show(const struct btf *btf, const struct btf_type *t,
1147 u32 type_id, void *data, u8 bits_offsets,
1148 struct seq_file *m)
1149{
1150 seq_printf(m, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
1151}
1152
1153static int btf_int_check_member(struct btf_verifier_env *env,
1154 const struct btf_type *struct_type,
1155 const struct btf_member *member,
1156 const struct btf_type *member_type)
1157{
1158 u32 int_data = btf_type_int(member_type);
1159 u32 struct_bits_off = member->offset;
1160 u32 struct_size = struct_type->size;
1161 u32 nr_copy_bits;
1162 u32 bytes_offset;
1163
1164 if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
1165 btf_verifier_log_member(env, struct_type, member,
1166 "bits_offset exceeds U32_MAX");
1167 return -EINVAL;
1168 }
1169
1170 struct_bits_off += BTF_INT_OFFSET(int_data);
1171 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1172 nr_copy_bits = BTF_INT_BITS(int_data) +
1173 BITS_PER_BYTE_MASKED(struct_bits_off);
1174
1175 if (nr_copy_bits > BITS_PER_U128) {
1176 btf_verifier_log_member(env, struct_type, member,
1177 "nr_copy_bits exceeds 128");
1178 return -EINVAL;
1179 }
1180
1181 if (struct_size < bytes_offset ||
1182 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
1183 btf_verifier_log_member(env, struct_type, member,
1184 "Member exceeds struct_size");
1185 return -EINVAL;
1186 }
1187
1188 return 0;
1189}
1190
1191static int btf_int_check_kflag_member(struct btf_verifier_env *env,
1192 const struct btf_type *struct_type,
1193 const struct btf_member *member,
1194 const struct btf_type *member_type)
1195{
1196 u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset;
1197 u32 int_data = btf_type_int(member_type);
1198 u32 struct_size = struct_type->size;
1199 u32 nr_copy_bits;
1200
1201 /* a regular int type is required for the kflag int member */
1202 if (!btf_type_int_is_regular(member_type)) {
1203 btf_verifier_log_member(env, struct_type, member,
1204 "Invalid member base type");
1205 return -EINVAL;
1206 }
1207
1208 /* check sanity of bitfield size */
1209 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
1210 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
1211 nr_int_data_bits = BTF_INT_BITS(int_data);
1212 if (!nr_bits) {
1213 /* Not a bitfield member, member offset must be at byte
1214 * boundary.
1215 */
1216 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
1217 btf_verifier_log_member(env, struct_type, member,
1218 "Invalid member offset");
1219 return -EINVAL;
1220 }
1221
1222 nr_bits = nr_int_data_bits;
1223 } else if (nr_bits > nr_int_data_bits) {
1224 btf_verifier_log_member(env, struct_type, member,
1225 "Invalid member bitfield_size");
1226 return -EINVAL;
1227 }
1228
1229 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1230 nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off);
1231 if (nr_copy_bits > BITS_PER_U128) {
1232 btf_verifier_log_member(env, struct_type, member,
1233 "nr_copy_bits exceeds 128");
1234 return -EINVAL;
1235 }
1236
1237 if (struct_size < bytes_offset ||
1238 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
1239 btf_verifier_log_member(env, struct_type, member,
1240 "Member exceeds struct_size");
1241 return -EINVAL;
1242 }
1243
1244 return 0;
1245}
1246
1247static s32 btf_int_check_meta(struct btf_verifier_env *env,
1248 const struct btf_type *t,
1249 u32 meta_left)
1250{
1251 u32 int_data, nr_bits, meta_needed = sizeof(int_data);
1252 u16 encoding;
1253
1254 if (meta_left < meta_needed) {
1255 btf_verifier_log_basic(env, t,
1256 "meta_left:%u meta_needed:%u",
1257 meta_left, meta_needed);
1258 return -EINVAL;
1259 }
1260
1261 if (btf_type_vlen(t)) {
1262 btf_verifier_log_type(env, t, "vlen != 0");
1263 return -EINVAL;
1264 }
1265
1266 if (btf_type_kflag(t)) {
1267 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
1268 return -EINVAL;
1269 }
1270
1271 int_data = btf_type_int(t);
1272 if (int_data & ~BTF_INT_MASK) {
1273 btf_verifier_log_basic(env, t, "Invalid int_data:%x",
1274 int_data);
1275 return -EINVAL;
1276 }
1277
1278 nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);
1279
1280 if (nr_bits > BITS_PER_U128) {
1281 btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
1282 BITS_PER_U128);
1283 return -EINVAL;
1284 }
1285
1286 if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
1287 btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
1288 return -EINVAL;
1289 }
1290
1291 /*
1292 * Only one of the encoding bits is allowed and it
1293 * should be sufficient for the pretty print purpose (i.e. decoding).
1294 * Multiple bits can be allowed later if it is found
1295 * to be insufficient.
1296 */
1297 encoding = BTF_INT_ENCODING(int_data);
1298 if (encoding &&
1299 encoding != BTF_INT_SIGNED &&
1300 encoding != BTF_INT_CHAR &&
1301 encoding != BTF_INT_BOOL) {
1302 btf_verifier_log_type(env, t, "Unsupported encoding");
1303 return -ENOTSUPP;
1304 }
1305
1306 btf_verifier_log_type(env, t, NULL);
1307
1308 return meta_needed;
1309}
1310
1311static void btf_int_log(struct btf_verifier_env *env,
1312 const struct btf_type *t)
1313{
1314 int int_data = btf_type_int(t);
1315
1316 btf_verifier_log(env,
1317 "size=%u bits_offset=%u nr_bits=%u encoding=%s",
1318 t->size, BTF_INT_OFFSET(int_data),
1319 BTF_INT_BITS(int_data),
1320 btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
1321}
1322
1323static void btf_int128_print(struct seq_file *m, void *data)
1324{
1325 /* data points to a __int128 number.
1326 * Suppose
1327 * int128_num = *(__int128 *)data;
1328 * The below formulas shows what upper_num and lower_num represents:
1329 * upper_num = int128_num >> 64;
1330 * lower_num = int128_num & 0xffffffffFFFFFFFFULL;
1331 */
1332 u64 upper_num, lower_num;
1333
1334#ifdef __BIG_ENDIAN_BITFIELD
1335 upper_num = *(u64 *)data;
1336 lower_num = *(u64 *)(data + 8);
1337#else
1338 upper_num = *(u64 *)(data + 8);
1339 lower_num = *(u64 *)data;
1340#endif
1341 if (upper_num == 0)
1342 seq_printf(m, "0x%llx", lower_num);
1343 else
1344 seq_printf(m, "0x%llx%016llx", upper_num, lower_num);
1345}
1346
1347static void btf_int128_shift(u64 *print_num, u16 left_shift_bits,
1348 u16 right_shift_bits)
1349{
1350 u64 upper_num, lower_num;
1351
1352#ifdef __BIG_ENDIAN_BITFIELD
1353 upper_num = print_num[0];
1354 lower_num = print_num[1];
1355#else
1356 upper_num = print_num[1];
1357 lower_num = print_num[0];
1358#endif
1359
1360 /* shake out un-needed bits by shift/or operations */
1361 if (left_shift_bits >= 64) {
1362 upper_num = lower_num << (left_shift_bits - 64);
1363 lower_num = 0;
1364 } else {
1365 upper_num = (upper_num << left_shift_bits) |
1366 (lower_num >> (64 - left_shift_bits));
1367 lower_num = lower_num << left_shift_bits;
1368 }
1369
1370 if (right_shift_bits >= 64) {
1371 lower_num = upper_num >> (right_shift_bits - 64);
1372 upper_num = 0;
1373 } else {
1374 lower_num = (lower_num >> right_shift_bits) |
1375 (upper_num << (64 - right_shift_bits));
1376 upper_num = upper_num >> right_shift_bits;
1377 }
1378
1379#ifdef __BIG_ENDIAN_BITFIELD
1380 print_num[0] = upper_num;
1381 print_num[1] = lower_num;
1382#else
1383 print_num[0] = lower_num;
1384 print_num[1] = upper_num;
1385#endif
1386}
1387
1388static void btf_bitfield_seq_show(void *data, u8 bits_offset,
1389 u8 nr_bits, struct seq_file *m)
1390{
1391 u16 left_shift_bits, right_shift_bits;
1392 u8 nr_copy_bytes;
1393 u8 nr_copy_bits;
1394 u64 print_num[2] = {};
1395
1396 nr_copy_bits = nr_bits + bits_offset;
1397 nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
1398
1399 memcpy(print_num, data, nr_copy_bytes);
1400
1401#ifdef __BIG_ENDIAN_BITFIELD
1402 left_shift_bits = bits_offset;
1403#else
1404 left_shift_bits = BITS_PER_U128 - nr_copy_bits;
1405#endif
1406 right_shift_bits = BITS_PER_U128 - nr_bits;
1407
1408 btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
1409 btf_int128_print(m, print_num);
1410}
1411
1412
1413static void btf_int_bits_seq_show(const struct btf *btf,
1414 const struct btf_type *t,
1415 void *data, u8 bits_offset,
1416 struct seq_file *m)
1417{
1418 u32 int_data = btf_type_int(t);
1419 u8 nr_bits = BTF_INT_BITS(int_data);
1420 u8 total_bits_offset;
1421
1422 /*
1423 * bits_offset is at most 7.
1424 * BTF_INT_OFFSET() cannot exceed 128 bits.
1425 */
1426 total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
1427 data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
1428 bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
1429 btf_bitfield_seq_show(data, bits_offset, nr_bits, m);
1430}
1431
1432static void btf_int_seq_show(const struct btf *btf, const struct btf_type *t,
1433 u32 type_id, void *data, u8 bits_offset,
1434 struct seq_file *m)
1435{
1436 u32 int_data = btf_type_int(t);
1437 u8 encoding = BTF_INT_ENCODING(int_data);
1438 bool sign = encoding & BTF_INT_SIGNED;
1439 u8 nr_bits = BTF_INT_BITS(int_data);
1440
1441 if (bits_offset || BTF_INT_OFFSET(int_data) ||
1442 BITS_PER_BYTE_MASKED(nr_bits)) {
1443 btf_int_bits_seq_show(btf, t, data, bits_offset, m);
1444 return;
1445 }
1446
1447 switch (nr_bits) {
1448 case 128:
1449 btf_int128_print(m, data);
1450 break;
1451 case 64:
1452 if (sign)
1453 seq_printf(m, "%lld", *(s64 *)data);
1454 else
1455 seq_printf(m, "%llu", *(u64 *)data);
1456 break;
1457 case 32:
1458 if (sign)
1459 seq_printf(m, "%d", *(s32 *)data);
1460 else
1461 seq_printf(m, "%u", *(u32 *)data);
1462 break;
1463 case 16:
1464 if (sign)
1465 seq_printf(m, "%d", *(s16 *)data);
1466 else
1467 seq_printf(m, "%u", *(u16 *)data);
1468 break;
1469 case 8:
1470 if (sign)
1471 seq_printf(m, "%d", *(s8 *)data);
1472 else
1473 seq_printf(m, "%u", *(u8 *)data);
1474 break;
1475 default:
1476 btf_int_bits_seq_show(btf, t, data, bits_offset, m);
1477 }
1478}
1479
1480static const struct btf_kind_operations int_ops = {
1481 .check_meta = btf_int_check_meta,
1482 .resolve = btf_df_resolve,
1483 .check_member = btf_int_check_member,
1484 .check_kflag_member = btf_int_check_kflag_member,
1485 .log_details = btf_int_log,
1486 .seq_show = btf_int_seq_show,
1487};
1488
1489static int btf_modifier_check_member(struct btf_verifier_env *env,
1490 const struct btf_type *struct_type,
1491 const struct btf_member *member,
1492 const struct btf_type *member_type)
1493{
1494 const struct btf_type *resolved_type;
1495 u32 resolved_type_id = member->type;
1496 struct btf_member resolved_member;
1497 struct btf *btf = env->btf;
1498
1499 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
1500 if (!resolved_type) {
1501 btf_verifier_log_member(env, struct_type, member,
1502 "Invalid member");
1503 return -EINVAL;
1504 }
1505
1506 resolved_member = *member;
1507 resolved_member.type = resolved_type_id;
1508
1509 return btf_type_ops(resolved_type)->check_member(env, struct_type,
1510 &resolved_member,
1511 resolved_type);
1512}
1513
1514static int btf_modifier_check_kflag_member(struct btf_verifier_env *env,
1515 const struct btf_type *struct_type,
1516 const struct btf_member *member,
1517 const struct btf_type *member_type)
1518{
1519 const struct btf_type *resolved_type;
1520 u32 resolved_type_id = member->type;
1521 struct btf_member resolved_member;
1522 struct btf *btf = env->btf;
1523
1524 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
1525 if (!resolved_type) {
1526 btf_verifier_log_member(env, struct_type, member,
1527 "Invalid member");
1528 return -EINVAL;
1529 }
1530
1531 resolved_member = *member;
1532 resolved_member.type = resolved_type_id;
1533
1534 return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type,
1535 &resolved_member,
1536 resolved_type);
1537}
1538
1539static int btf_ptr_check_member(struct btf_verifier_env *env,
1540 const struct btf_type *struct_type,
1541 const struct btf_member *member,
1542 const struct btf_type *member_type)
1543{
1544 u32 struct_size, struct_bits_off, bytes_offset;
1545
1546 struct_size = struct_type->size;
1547 struct_bits_off = member->offset;
1548 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1549
1550 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
1551 btf_verifier_log_member(env, struct_type, member,
1552 "Member is not byte aligned");
1553 return -EINVAL;
1554 }
1555
1556 if (struct_size - bytes_offset < sizeof(void *)) {
1557 btf_verifier_log_member(env, struct_type, member,
1558 "Member exceeds struct_size");
1559 return -EINVAL;
1560 }
1561
1562 return 0;
1563}
1564
1565static int btf_ref_type_check_meta(struct btf_verifier_env *env,
1566 const struct btf_type *t,
1567 u32 meta_left)
1568{
1569 if (btf_type_vlen(t)) {
1570 btf_verifier_log_type(env, t, "vlen != 0");
1571 return -EINVAL;
1572 }
1573
1574 if (btf_type_kflag(t)) {
1575 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
1576 return -EINVAL;
1577 }
1578
1579 if (!BTF_TYPE_ID_VALID(t->type)) {
1580 btf_verifier_log_type(env, t, "Invalid type_id");
1581 return -EINVAL;
1582 }
1583
1584 /* typedef type must have a valid name, and other ref types,
1585 * volatile, const, restrict, should have a null name.
1586 */
1587 if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
1588 if (!t->name_off ||
1589 !btf_name_valid_identifier(env->btf, t->name_off)) {
1590 btf_verifier_log_type(env, t, "Invalid name");
1591 return -EINVAL;
1592 }
1593 } else {
1594 if (t->name_off) {
1595 btf_verifier_log_type(env, t, "Invalid name");
1596 return -EINVAL;
1597 }
1598 }
1599
1600 btf_verifier_log_type(env, t, NULL);
1601
1602 return 0;
1603}
1604
1605static int btf_modifier_resolve(struct btf_verifier_env *env,
1606 const struct resolve_vertex *v)
1607{
1608 const struct btf_type *t = v->t;
1609 const struct btf_type *next_type;
1610 u32 next_type_id = t->type;
1611 struct btf *btf = env->btf;
1612
1613 next_type = btf_type_by_id(btf, next_type_id);
1614 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
1615 btf_verifier_log_type(env, v->t, "Invalid type_id");
1616 return -EINVAL;
1617 }
1618
1619 if (!env_type_is_resolve_sink(env, next_type) &&
1620 !env_type_is_resolved(env, next_type_id))
1621 return env_stack_push(env, next_type, next_type_id);
1622
1623 /* Figure out the resolved next_type_id with size.
1624 * They will be stored in the current modifier's
1625 * resolved_ids and resolved_sizes such that it can
1626 * save us a few type-following when we use it later (e.g. in
1627 * pretty print).
1628 */
1629 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
1630 if (env_type_is_resolved(env, next_type_id))
1631 next_type = btf_type_id_resolve(btf, &next_type_id);
1632
1633 /* "typedef void new_void", "const void"...etc */
1634 if (!btf_type_is_void(next_type) &&
1635 !btf_type_is_fwd(next_type) &&
1636 !btf_type_is_func_proto(next_type)) {
1637 btf_verifier_log_type(env, v->t, "Invalid type_id");
1638 return -EINVAL;
1639 }
1640 }
1641
1642 env_stack_pop_resolved(env, next_type_id, 0);
1643
1644 return 0;
1645}
1646
1647static int btf_var_resolve(struct btf_verifier_env *env,
1648 const struct resolve_vertex *v)
1649{
1650 const struct btf_type *next_type;
1651 const struct btf_type *t = v->t;
1652 u32 next_type_id = t->type;
1653 struct btf *btf = env->btf;
1654
1655 next_type = btf_type_by_id(btf, next_type_id);
1656 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
1657 btf_verifier_log_type(env, v->t, "Invalid type_id");
1658 return -EINVAL;
1659 }
1660
1661 if (!env_type_is_resolve_sink(env, next_type) &&
1662 !env_type_is_resolved(env, next_type_id))
1663 return env_stack_push(env, next_type, next_type_id);
1664
1665 if (btf_type_is_modifier(next_type)) {
1666 const struct btf_type *resolved_type;
1667 u32 resolved_type_id;
1668
1669 resolved_type_id = next_type_id;
1670 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
1671
1672 if (btf_type_is_ptr(resolved_type) &&
1673 !env_type_is_resolve_sink(env, resolved_type) &&
1674 !env_type_is_resolved(env, resolved_type_id))
1675 return env_stack_push(env, resolved_type,
1676 resolved_type_id);
1677 }
1678
1679 /* We must resolve to something concrete at this point, no
1680 * forward types or similar that would resolve to size of
1681 * zero is allowed.
1682 */
1683 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
1684 btf_verifier_log_type(env, v->t, "Invalid type_id");
1685 return -EINVAL;
1686 }
1687
1688 env_stack_pop_resolved(env, next_type_id, 0);
1689
1690 return 0;
1691}
1692
1693static int btf_ptr_resolve(struct btf_verifier_env *env,
1694 const struct resolve_vertex *v)
1695{
1696 const struct btf_type *next_type;
1697 const struct btf_type *t = v->t;
1698 u32 next_type_id = t->type;
1699 struct btf *btf = env->btf;
1700
1701 next_type = btf_type_by_id(btf, next_type_id);
1702 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
1703 btf_verifier_log_type(env, v->t, "Invalid type_id");
1704 return -EINVAL;
1705 }
1706
1707 if (!env_type_is_resolve_sink(env, next_type) &&
1708 !env_type_is_resolved(env, next_type_id))
1709 return env_stack_push(env, next_type, next_type_id);
1710
1711 /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
1712 * the modifier may have stopped resolving when it was resolved
1713 * to a ptr (last-resolved-ptr).
1714 *
1715 * We now need to continue from the last-resolved-ptr to
1716 * ensure the last-resolved-ptr will not referring back to
1717 * the currenct ptr (t).
1718 */
1719 if (btf_type_is_modifier(next_type)) {
1720 const struct btf_type *resolved_type;
1721 u32 resolved_type_id;
1722
1723 resolved_type_id = next_type_id;
1724 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
1725
1726 if (btf_type_is_ptr(resolved_type) &&
1727 !env_type_is_resolve_sink(env, resolved_type) &&
1728 !env_type_is_resolved(env, resolved_type_id))
1729 return env_stack_push(env, resolved_type,
1730 resolved_type_id);
1731 }
1732
1733 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
1734 if (env_type_is_resolved(env, next_type_id))
1735 next_type = btf_type_id_resolve(btf, &next_type_id);
1736
1737 if (!btf_type_is_void(next_type) &&
1738 !btf_type_is_fwd(next_type) &&
1739 !btf_type_is_func_proto(next_type)) {
1740 btf_verifier_log_type(env, v->t, "Invalid type_id");
1741 return -EINVAL;
1742 }
1743 }
1744
1745 env_stack_pop_resolved(env, next_type_id, 0);
1746
1747 return 0;
1748}
1749
1750static void btf_modifier_seq_show(const struct btf *btf,
1751 const struct btf_type *t,
1752 u32 type_id, void *data,
1753 u8 bits_offset, struct seq_file *m)
1754{
1755 t = btf_type_id_resolve(btf, &type_id);
1756
1757 btf_type_ops(t)->seq_show(btf, t, type_id, data, bits_offset, m);
1758}
1759
1760static void btf_var_seq_show(const struct btf *btf, const struct btf_type *t,
1761 u32 type_id, void *data, u8 bits_offset,
1762 struct seq_file *m)
1763{
1764 t = btf_type_id_resolve(btf, &type_id);
1765
1766 btf_type_ops(t)->seq_show(btf, t, type_id, data, bits_offset, m);
1767}
1768
1769static void btf_ptr_seq_show(const struct btf *btf, const struct btf_type *t,
1770 u32 type_id, void *data, u8 bits_offset,
1771 struct seq_file *m)
1772{
1773 /* It is a hashed value */
1774 seq_printf(m, "%p", *(void **)data);
1775}
1776
1777static void btf_ref_type_log(struct btf_verifier_env *env,
1778 const struct btf_type *t)
1779{
1780 btf_verifier_log(env, "type_id=%u", t->type);
1781}
1782
1783static struct btf_kind_operations modifier_ops = {
1784 .check_meta = btf_ref_type_check_meta,
1785 .resolve = btf_modifier_resolve,
1786 .check_member = btf_modifier_check_member,
1787 .check_kflag_member = btf_modifier_check_kflag_member,
1788 .log_details = btf_ref_type_log,
1789 .seq_show = btf_modifier_seq_show,
1790};
1791
1792static struct btf_kind_operations ptr_ops = {
1793 .check_meta = btf_ref_type_check_meta,
1794 .resolve = btf_ptr_resolve,
1795 .check_member = btf_ptr_check_member,
1796 .check_kflag_member = btf_generic_check_kflag_member,
1797 .log_details = btf_ref_type_log,
1798 .seq_show = btf_ptr_seq_show,
1799};
1800
1801static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
1802 const struct btf_type *t,
1803 u32 meta_left)
1804{
1805 if (btf_type_vlen(t)) {
1806 btf_verifier_log_type(env, t, "vlen != 0");
1807 return -EINVAL;
1808 }
1809
1810 if (t->type) {
1811 btf_verifier_log_type(env, t, "type != 0");
1812 return -EINVAL;
1813 }
1814
1815 /* fwd type must have a valid name */
1816 if (!t->name_off ||
1817 !btf_name_valid_identifier(env->btf, t->name_off)) {
1818 btf_verifier_log_type(env, t, "Invalid name");
1819 return -EINVAL;
1820 }
1821
1822 btf_verifier_log_type(env, t, NULL);
1823
1824 return 0;
1825}
1826
1827static void btf_fwd_type_log(struct btf_verifier_env *env,
1828 const struct btf_type *t)
1829{
1830 btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct");
1831}
1832
1833static struct btf_kind_operations fwd_ops = {
1834 .check_meta = btf_fwd_check_meta,
1835 .resolve = btf_df_resolve,
1836 .check_member = btf_df_check_member,
1837 .check_kflag_member = btf_df_check_kflag_member,
1838 .log_details = btf_fwd_type_log,
1839 .seq_show = btf_df_seq_show,
1840};
1841
1842static int btf_array_check_member(struct btf_verifier_env *env,
1843 const struct btf_type *struct_type,
1844 const struct btf_member *member,
1845 const struct btf_type *member_type)
1846{
1847 u32 struct_bits_off = member->offset;
1848 u32 struct_size, bytes_offset;
1849 u32 array_type_id, array_size;
1850 struct btf *btf = env->btf;
1851
1852 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
1853 btf_verifier_log_member(env, struct_type, member,
1854 "Member is not byte aligned");
1855 return -EINVAL;
1856 }
1857
1858 array_type_id = member->type;
1859 btf_type_id_size(btf, &array_type_id, &array_size);
1860 struct_size = struct_type->size;
1861 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1862 if (struct_size - bytes_offset < array_size) {
1863 btf_verifier_log_member(env, struct_type, member,
1864 "Member exceeds struct_size");
1865 return -EINVAL;
1866 }
1867
1868 return 0;
1869}
1870
1871static s32 btf_array_check_meta(struct btf_verifier_env *env,
1872 const struct btf_type *t,
1873 u32 meta_left)
1874{
1875 const struct btf_array *array = btf_type_array(t);
1876 u32 meta_needed = sizeof(*array);
1877
1878 if (meta_left < meta_needed) {
1879 btf_verifier_log_basic(env, t,
1880 "meta_left:%u meta_needed:%u",
1881 meta_left, meta_needed);
1882 return -EINVAL;
1883 }
1884
1885 /* array type should not have a name */
1886 if (t->name_off) {
1887 btf_verifier_log_type(env, t, "Invalid name");
1888 return -EINVAL;
1889 }
1890
1891 if (btf_type_vlen(t)) {
1892 btf_verifier_log_type(env, t, "vlen != 0");
1893 return -EINVAL;
1894 }
1895
1896 if (btf_type_kflag(t)) {
1897 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
1898 return -EINVAL;
1899 }
1900
1901 if (t->size) {
1902 btf_verifier_log_type(env, t, "size != 0");
1903 return -EINVAL;
1904 }
1905
1906 /* Array elem type and index type cannot be in type void,
1907 * so !array->type and !array->index_type are not allowed.
1908 */
1909 if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
1910 btf_verifier_log_type(env, t, "Invalid elem");
1911 return -EINVAL;
1912 }
1913
1914 if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
1915 btf_verifier_log_type(env, t, "Invalid index");
1916 return -EINVAL;
1917 }
1918
1919 btf_verifier_log_type(env, t, NULL);
1920
1921 return meta_needed;
1922}
1923
1924static int btf_array_resolve(struct btf_verifier_env *env,
1925 const struct resolve_vertex *v)
1926{
1927 const struct btf_array *array = btf_type_array(v->t);
1928 const struct btf_type *elem_type, *index_type;
1929 u32 elem_type_id, index_type_id;
1930 struct btf *btf = env->btf;
1931 u32 elem_size;
1932
1933 /* Check array->index_type */
1934 index_type_id = array->index_type;
1935 index_type = btf_type_by_id(btf, index_type_id);
1936 if (btf_type_nosize_or_null(index_type) ||
1937 btf_type_is_resolve_source_only(index_type)) {
1938 btf_verifier_log_type(env, v->t, "Invalid index");
1939 return -EINVAL;
1940 }
1941
1942 if (!env_type_is_resolve_sink(env, index_type) &&
1943 !env_type_is_resolved(env, index_type_id))
1944 return env_stack_push(env, index_type, index_type_id);
1945
1946 index_type = btf_type_id_size(btf, &index_type_id, NULL);
1947 if (!index_type || !btf_type_is_int(index_type) ||
1948 !btf_type_int_is_regular(index_type)) {
1949 btf_verifier_log_type(env, v->t, "Invalid index");
1950 return -EINVAL;
1951 }
1952
1953 /* Check array->type */
1954 elem_type_id = array->type;
1955 elem_type = btf_type_by_id(btf, elem_type_id);
1956 if (btf_type_nosize_or_null(elem_type) ||
1957 btf_type_is_resolve_source_only(elem_type)) {
1958 btf_verifier_log_type(env, v->t,
1959 "Invalid elem");
1960 return -EINVAL;
1961 }
1962
1963 if (!env_type_is_resolve_sink(env, elem_type) &&
1964 !env_type_is_resolved(env, elem_type_id))
1965 return env_stack_push(env, elem_type, elem_type_id);
1966
1967 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
1968 if (!elem_type) {
1969 btf_verifier_log_type(env, v->t, "Invalid elem");
1970 return -EINVAL;
1971 }
1972
1973 if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
1974 btf_verifier_log_type(env, v->t, "Invalid array of int");
1975 return -EINVAL;
1976 }
1977
1978 if (array->nelems && elem_size > U32_MAX / array->nelems) {
1979 btf_verifier_log_type(env, v->t,
1980 "Array size overflows U32_MAX");
1981 return -EINVAL;
1982 }
1983
1984 env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);
1985
1986 return 0;
1987}
1988
1989static void btf_array_log(struct btf_verifier_env *env,
1990 const struct btf_type *t)
1991{
1992 const struct btf_array *array = btf_type_array(t);
1993
1994 btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
1995 array->type, array->index_type, array->nelems);
1996}
1997
1998static void btf_array_seq_show(const struct btf *btf, const struct btf_type *t,
1999 u32 type_id, void *data, u8 bits_offset,
2000 struct seq_file *m)
2001{
2002 const struct btf_array *array = btf_type_array(t);
2003 const struct btf_kind_operations *elem_ops;
2004 const struct btf_type *elem_type;
2005 u32 i, elem_size, elem_type_id;
2006
2007 elem_type_id = array->type;
2008 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
2009 elem_ops = btf_type_ops(elem_type);
2010 seq_puts(m, "[");
2011 for (i = 0; i < array->nelems; i++) {
2012 if (i)
2013 seq_puts(m, ",");
2014
2015 elem_ops->seq_show(btf, elem_type, elem_type_id, data,
2016 bits_offset, m);
2017 data += elem_size;
2018 }
2019 seq_puts(m, "]");
2020}
2021
2022static struct btf_kind_operations array_ops = {
2023 .check_meta = btf_array_check_meta,
2024 .resolve = btf_array_resolve,
2025 .check_member = btf_array_check_member,
2026 .check_kflag_member = btf_generic_check_kflag_member,
2027 .log_details = btf_array_log,
2028 .seq_show = btf_array_seq_show,
2029};
2030
2031static int btf_struct_check_member(struct btf_verifier_env *env,
2032 const struct btf_type *struct_type,
2033 const struct btf_member *member,
2034 const struct btf_type *member_type)
2035{
2036 u32 struct_bits_off = member->offset;
2037 u32 struct_size, bytes_offset;
2038
2039 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2040 btf_verifier_log_member(env, struct_type, member,
2041 "Member is not byte aligned");
2042 return -EINVAL;
2043 }
2044
2045 struct_size = struct_type->size;
2046 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2047 if (struct_size - bytes_offset < member_type->size) {
2048 btf_verifier_log_member(env, struct_type, member,
2049 "Member exceeds struct_size");
2050 return -EINVAL;
2051 }
2052
2053 return 0;
2054}
2055
2056static s32 btf_struct_check_meta(struct btf_verifier_env *env,
2057 const struct btf_type *t,
2058 u32 meta_left)
2059{
2060 bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
2061 const struct btf_member *member;
2062 u32 meta_needed, last_offset;
2063 struct btf *btf = env->btf;
2064 u32 struct_size = t->size;
2065 u32 offset;
2066 u16 i;
2067
2068 meta_needed = btf_type_vlen(t) * sizeof(*member);
2069 if (meta_left < meta_needed) {
2070 btf_verifier_log_basic(env, t,
2071 "meta_left:%u meta_needed:%u",
2072 meta_left, meta_needed);
2073 return -EINVAL;
2074 }
2075
2076 /* struct type either no name or a valid one */
2077 if (t->name_off &&
2078 !btf_name_valid_identifier(env->btf, t->name_off)) {
2079 btf_verifier_log_type(env, t, "Invalid name");
2080 return -EINVAL;
2081 }
2082
2083 btf_verifier_log_type(env, t, NULL);
2084
2085 last_offset = 0;
2086 for_each_member(i, t, member) {
2087 if (!btf_name_offset_valid(btf, member->name_off)) {
2088 btf_verifier_log_member(env, t, member,
2089 "Invalid member name_offset:%u",
2090 member->name_off);
2091 return -EINVAL;
2092 }
2093
2094 /* struct member either no name or a valid one */
2095 if (member->name_off &&
2096 !btf_name_valid_identifier(btf, member->name_off)) {
2097 btf_verifier_log_member(env, t, member, "Invalid name");
2098 return -EINVAL;
2099 }
2100 /* A member cannot be in type void */
2101 if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
2102 btf_verifier_log_member(env, t, member,
2103 "Invalid type_id");
2104 return -EINVAL;
2105 }
2106
2107 offset = btf_member_bit_offset(t, member);
2108 if (is_union && offset) {
2109 btf_verifier_log_member(env, t, member,
2110 "Invalid member bits_offset");
2111 return -EINVAL;
2112 }
2113
2114 /*
2115 * ">" instead of ">=" because the last member could be
2116 * "char a[0];"
2117 */
2118 if (last_offset > offset) {
2119 btf_verifier_log_member(env, t, member,
2120 "Invalid member bits_offset");
2121 return -EINVAL;
2122 }
2123
2124 if (BITS_ROUNDUP_BYTES(offset) > struct_size) {
2125 btf_verifier_log_member(env, t, member,
2126 "Member bits_offset exceeds its struct size");
2127 return -EINVAL;
2128 }
2129
2130 btf_verifier_log_member(env, t, member, NULL);
2131 last_offset = offset;
2132 }
2133
2134 return meta_needed;
2135}
2136
2137static int btf_struct_resolve(struct btf_verifier_env *env,
2138 const struct resolve_vertex *v)
2139{
2140 const struct btf_member *member;
2141 int err;
2142 u16 i;
2143
2144 /* Before continue resolving the next_member,
2145 * ensure the last member is indeed resolved to a
2146 * type with size info.
2147 */
2148 if (v->next_member) {
2149 const struct btf_type *last_member_type;
2150 const struct btf_member *last_member;
2151 u16 last_member_type_id;
2152
2153 last_member = btf_type_member(v->t) + v->next_member - 1;
2154 last_member_type_id = last_member->type;
2155 if (WARN_ON_ONCE(!env_type_is_resolved(env,
2156 last_member_type_id)))
2157 return -EINVAL;
2158
2159 last_member_type = btf_type_by_id(env->btf,
2160 last_member_type_id);
2161 if (btf_type_kflag(v->t))
2162 err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t,
2163 last_member,
2164 last_member_type);
2165 else
2166 err = btf_type_ops(last_member_type)->check_member(env, v->t,
2167 last_member,
2168 last_member_type);
2169 if (err)
2170 return err;
2171 }
2172
2173 for_each_member_from(i, v->next_member, v->t, member) {
2174 u32 member_type_id = member->type;
2175 const struct btf_type *member_type = btf_type_by_id(env->btf,
2176 member_type_id);
2177
2178 if (btf_type_nosize_or_null(member_type) ||
2179 btf_type_is_resolve_source_only(member_type)) {
2180 btf_verifier_log_member(env, v->t, member,
2181 "Invalid member");
2182 return -EINVAL;
2183 }
2184
2185 if (!env_type_is_resolve_sink(env, member_type) &&
2186 !env_type_is_resolved(env, member_type_id)) {
2187 env_stack_set_next_member(env, i + 1);
2188 return env_stack_push(env, member_type, member_type_id);
2189 }
2190
2191 if (btf_type_kflag(v->t))
2192 err = btf_type_ops(member_type)->check_kflag_member(env, v->t,
2193 member,
2194 member_type);
2195 else
2196 err = btf_type_ops(member_type)->check_member(env, v->t,
2197 member,
2198 member_type);
2199 if (err)
2200 return err;
2201 }
2202
2203 env_stack_pop_resolved(env, 0, 0);
2204
2205 return 0;
2206}
2207
2208static void btf_struct_log(struct btf_verifier_env *env,
2209 const struct btf_type *t)
2210{
2211 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
2212}
2213
2214/* find 'struct bpf_spin_lock' in map value.
2215 * return >= 0 offset if found
2216 * and < 0 in case of error
2217 */
2218int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t)
2219{
2220 const struct btf_member *member;
2221 u32 i, off = -ENOENT;
2222
2223 if (!__btf_type_is_struct(t))
2224 return -EINVAL;
2225
2226 for_each_member(i, t, member) {
2227 const struct btf_type *member_type = btf_type_by_id(btf,
2228 member->type);
2229 if (!__btf_type_is_struct(member_type))
2230 continue;
2231 if (member_type->size != sizeof(struct bpf_spin_lock))
2232 continue;
2233 if (strcmp(__btf_name_by_offset(btf, member_type->name_off),
2234 "bpf_spin_lock"))
2235 continue;
2236 if (off != -ENOENT)
2237 /* only one 'struct bpf_spin_lock' is allowed */
2238 return -E2BIG;
2239 off = btf_member_bit_offset(t, member);
2240 if (off % 8)
2241 /* valid C code cannot generate such BTF */
2242 return -EINVAL;
2243 off /= 8;
2244 if (off % __alignof__(struct bpf_spin_lock))
2245 /* valid struct bpf_spin_lock will be 4 byte aligned */
2246 return -EINVAL;
2247 }
2248 return off;
2249}
2250
2251static void btf_struct_seq_show(const struct btf *btf, const struct btf_type *t,
2252 u32 type_id, void *data, u8 bits_offset,
2253 struct seq_file *m)
2254{
2255 const char *seq = BTF_INFO_KIND(t->info) == BTF_KIND_UNION ? "|" : ",";
2256 const struct btf_member *member;
2257 u32 i;
2258
2259 seq_puts(m, "{");
2260 for_each_member(i, t, member) {
2261 const struct btf_type *member_type = btf_type_by_id(btf,
2262 member->type);
2263 const struct btf_kind_operations *ops;
2264 u32 member_offset, bitfield_size;
2265 u32 bytes_offset;
2266 u8 bits8_offset;
2267
2268 if (i)
2269 seq_puts(m, seq);
2270
2271 member_offset = btf_member_bit_offset(t, member);
2272 bitfield_size = btf_member_bitfield_size(t, member);
2273 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
2274 bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
2275 if (bitfield_size) {
2276 btf_bitfield_seq_show(data + bytes_offset, bits8_offset,
2277 bitfield_size, m);
2278 } else {
2279 ops = btf_type_ops(member_type);
2280 ops->seq_show(btf, member_type, member->type,
2281 data + bytes_offset, bits8_offset, m);
2282 }
2283 }
2284 seq_puts(m, "}");
2285}
2286
2287static struct btf_kind_operations struct_ops = {
2288 .check_meta = btf_struct_check_meta,
2289 .resolve = btf_struct_resolve,
2290 .check_member = btf_struct_check_member,
2291 .check_kflag_member = btf_generic_check_kflag_member,
2292 .log_details = btf_struct_log,
2293 .seq_show = btf_struct_seq_show,
2294};
2295
2296static int btf_enum_check_member(struct btf_verifier_env *env,
2297 const struct btf_type *struct_type,
2298 const struct btf_member *member,
2299 const struct btf_type *member_type)
2300{
2301 u32 struct_bits_off = member->offset;
2302 u32 struct_size, bytes_offset;
2303
2304 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2305 btf_verifier_log_member(env, struct_type, member,
2306 "Member is not byte aligned");
2307 return -EINVAL;
2308 }
2309
2310 struct_size = struct_type->size;
2311 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2312 if (struct_size - bytes_offset < sizeof(int)) {
2313 btf_verifier_log_member(env, struct_type, member,
2314 "Member exceeds struct_size");
2315 return -EINVAL;
2316 }
2317
2318 return 0;
2319}
2320
2321static int btf_enum_check_kflag_member(struct btf_verifier_env *env,
2322 const struct btf_type *struct_type,
2323 const struct btf_member *member,
2324 const struct btf_type *member_type)
2325{
2326 u32 struct_bits_off, nr_bits, bytes_end, struct_size;
2327 u32 int_bitsize = sizeof(int) * BITS_PER_BYTE;
2328
2329 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
2330 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
2331 if (!nr_bits) {
2332 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2333 btf_verifier_log_member(env, struct_type, member,
2334 "Member is not byte aligned");
2335 return -EINVAL;
2336 }
2337
2338 nr_bits = int_bitsize;
2339 } else if (nr_bits > int_bitsize) {
2340 btf_verifier_log_member(env, struct_type, member,
2341 "Invalid member bitfield_size");
2342 return -EINVAL;
2343 }
2344
2345 struct_size = struct_type->size;
2346 bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits);
2347 if (struct_size < bytes_end) {
2348 btf_verifier_log_member(env, struct_type, member,
2349 "Member exceeds struct_size");
2350 return -EINVAL;
2351 }
2352
2353 return 0;
2354}
2355
2356static s32 btf_enum_check_meta(struct btf_verifier_env *env,
2357 const struct btf_type *t,
2358 u32 meta_left)
2359{
2360 const struct btf_enum *enums = btf_type_enum(t);
2361 struct btf *btf = env->btf;
2362 u16 i, nr_enums;
2363 u32 meta_needed;
2364
2365 nr_enums = btf_type_vlen(t);
2366 meta_needed = nr_enums * sizeof(*enums);
2367
2368 if (meta_left < meta_needed) {
2369 btf_verifier_log_basic(env, t,
2370 "meta_left:%u meta_needed:%u",
2371 meta_left, meta_needed);
2372 return -EINVAL;
2373 }
2374
2375 if (btf_type_kflag(t)) {
2376 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2377 return -EINVAL;
2378 }
2379
2380 if (t->size > 8 || !is_power_of_2(t->size)) {
2381 btf_verifier_log_type(env, t, "Unexpected size");
2382 return -EINVAL;
2383 }
2384
2385 /* enum type either no name or a valid one */
2386 if (t->name_off &&
2387 !btf_name_valid_identifier(env->btf, t->name_off)) {
2388 btf_verifier_log_type(env, t, "Invalid name");
2389 return -EINVAL;
2390 }
2391
2392 btf_verifier_log_type(env, t, NULL);
2393
2394 for (i = 0; i < nr_enums; i++) {
2395 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
2396 btf_verifier_log(env, "\tInvalid name_offset:%u",
2397 enums[i].name_off);
2398 return -EINVAL;
2399 }
2400
2401 /* enum member must have a valid name */
2402 if (!enums[i].name_off ||
2403 !btf_name_valid_identifier(btf, enums[i].name_off)) {
2404 btf_verifier_log_type(env, t, "Invalid name");
2405 return -EINVAL;
2406 }
2407
2408
2409 btf_verifier_log(env, "\t%s val=%d\n",
2410 __btf_name_by_offset(btf, enums[i].name_off),
2411 enums[i].val);
2412 }
2413
2414 return meta_needed;
2415}
2416
2417static void btf_enum_log(struct btf_verifier_env *env,
2418 const struct btf_type *t)
2419{
2420 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
2421}
2422
2423static void btf_enum_seq_show(const struct btf *btf, const struct btf_type *t,
2424 u32 type_id, void *data, u8 bits_offset,
2425 struct seq_file *m)
2426{
2427 const struct btf_enum *enums = btf_type_enum(t);
2428 u32 i, nr_enums = btf_type_vlen(t);
2429 int v = *(int *)data;
2430
2431 for (i = 0; i < nr_enums; i++) {
2432 if (v == enums[i].val) {
2433 seq_printf(m, "%s",
2434 __btf_name_by_offset(btf,
2435 enums[i].name_off));
2436 return;
2437 }
2438 }
2439
2440 seq_printf(m, "%d", v);
2441}
2442
2443static struct btf_kind_operations enum_ops = {
2444 .check_meta = btf_enum_check_meta,
2445 .resolve = btf_df_resolve,
2446 .check_member = btf_enum_check_member,
2447 .check_kflag_member = btf_enum_check_kflag_member,
2448 .log_details = btf_enum_log,
2449 .seq_show = btf_enum_seq_show,
2450};
2451
2452static s32 btf_func_proto_check_meta(struct btf_verifier_env *env,
2453 const struct btf_type *t,
2454 u32 meta_left)
2455{
2456 u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param);
2457
2458 if (meta_left < meta_needed) {
2459 btf_verifier_log_basic(env, t,
2460 "meta_left:%u meta_needed:%u",
2461 meta_left, meta_needed);
2462 return -EINVAL;
2463 }
2464
2465 if (t->name_off) {
2466 btf_verifier_log_type(env, t, "Invalid name");
2467 return -EINVAL;
2468 }
2469
2470 if (btf_type_kflag(t)) {
2471 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2472 return -EINVAL;
2473 }
2474
2475 btf_verifier_log_type(env, t, NULL);
2476
2477 return meta_needed;
2478}
2479
2480static void btf_func_proto_log(struct btf_verifier_env *env,
2481 const struct btf_type *t)
2482{
2483 const struct btf_param *args = (const struct btf_param *)(t + 1);
2484 u16 nr_args = btf_type_vlen(t), i;
2485
2486 btf_verifier_log(env, "return=%u args=(", t->type);
2487 if (!nr_args) {
2488 btf_verifier_log(env, "void");
2489 goto done;
2490 }
2491
2492 if (nr_args == 1 && !args[0].type) {
2493 /* Only one vararg */
2494 btf_verifier_log(env, "vararg");
2495 goto done;
2496 }
2497
2498 btf_verifier_log(env, "%u %s", args[0].type,
2499 __btf_name_by_offset(env->btf,
2500 args[0].name_off));
2501 for (i = 1; i < nr_args - 1; i++)
2502 btf_verifier_log(env, ", %u %s", args[i].type,
2503 __btf_name_by_offset(env->btf,
2504 args[i].name_off));
2505
2506 if (nr_args > 1) {
2507 const struct btf_param *last_arg = &args[nr_args - 1];
2508
2509 if (last_arg->type)
2510 btf_verifier_log(env, ", %u %s", last_arg->type,
2511 __btf_name_by_offset(env->btf,
2512 last_arg->name_off));
2513 else
2514 btf_verifier_log(env, ", vararg");
2515 }
2516
2517done:
2518 btf_verifier_log(env, ")");
2519}
2520
2521static struct btf_kind_operations func_proto_ops = {
2522 .check_meta = btf_func_proto_check_meta,
2523 .resolve = btf_df_resolve,
2524 /*
2525 * BTF_KIND_FUNC_PROTO cannot be directly referred by
2526 * a struct's member.
2527 *
2528 * It should be a funciton pointer instead.
2529 * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO)
2530 *
2531 * Hence, there is no btf_func_check_member().
2532 */
2533 .check_member = btf_df_check_member,
2534 .check_kflag_member = btf_df_check_kflag_member,
2535 .log_details = btf_func_proto_log,
2536 .seq_show = btf_df_seq_show,
2537};
2538
2539static s32 btf_func_check_meta(struct btf_verifier_env *env,
2540 const struct btf_type *t,
2541 u32 meta_left)
2542{
2543 if (!t->name_off ||
2544 !btf_name_valid_identifier(env->btf, t->name_off)) {
2545 btf_verifier_log_type(env, t, "Invalid name");
2546 return -EINVAL;
2547 }
2548
2549 if (btf_type_vlen(t)) {
2550 btf_verifier_log_type(env, t, "vlen != 0");
2551 return -EINVAL;
2552 }
2553
2554 if (btf_type_kflag(t)) {
2555 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2556 return -EINVAL;
2557 }
2558
2559 btf_verifier_log_type(env, t, NULL);
2560
2561 return 0;
2562}
2563
2564static struct btf_kind_operations func_ops = {
2565 .check_meta = btf_func_check_meta,
2566 .resolve = btf_df_resolve,
2567 .check_member = btf_df_check_member,
2568 .check_kflag_member = btf_df_check_kflag_member,
2569 .log_details = btf_ref_type_log,
2570 .seq_show = btf_df_seq_show,
2571};
2572
2573static s32 btf_var_check_meta(struct btf_verifier_env *env,
2574 const struct btf_type *t,
2575 u32 meta_left)
2576{
2577 const struct btf_var *var;
2578 u32 meta_needed = sizeof(*var);
2579
2580 if (meta_left < meta_needed) {
2581 btf_verifier_log_basic(env, t,
2582 "meta_left:%u meta_needed:%u",
2583 meta_left, meta_needed);
2584 return -EINVAL;
2585 }
2586
2587 if (btf_type_vlen(t)) {
2588 btf_verifier_log_type(env, t, "vlen != 0");
2589 return -EINVAL;
2590 }
2591
2592 if (btf_type_kflag(t)) {
2593 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2594 return -EINVAL;
2595 }
2596
2597 if (!t->name_off ||
2598 !__btf_name_valid(env->btf, t->name_off, true)) {
2599 btf_verifier_log_type(env, t, "Invalid name");
2600 return -EINVAL;
2601 }
2602
2603 /* A var cannot be in type void */
2604 if (!t->type || !BTF_TYPE_ID_VALID(t->type)) {
2605 btf_verifier_log_type(env, t, "Invalid type_id");
2606 return -EINVAL;
2607 }
2608
2609 var = btf_type_var(t);
2610 if (var->linkage != BTF_VAR_STATIC &&
2611 var->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
2612 btf_verifier_log_type(env, t, "Linkage not supported");
2613 return -EINVAL;
2614 }
2615
2616 btf_verifier_log_type(env, t, NULL);
2617
2618 return meta_needed;
2619}
2620
2621static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t)
2622{
2623 const struct btf_var *var = btf_type_var(t);
2624
2625 btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage);
2626}
2627
2628static const struct btf_kind_operations var_ops = {
2629 .check_meta = btf_var_check_meta,
2630 .resolve = btf_var_resolve,
2631 .check_member = btf_df_check_member,
2632 .check_kflag_member = btf_df_check_kflag_member,
2633 .log_details = btf_var_log,
2634 .seq_show = btf_var_seq_show,
2635};
2636
2637static s32 btf_datasec_check_meta(struct btf_verifier_env *env,
2638 const struct btf_type *t,
2639 u32 meta_left)
2640{
2641 const struct btf_var_secinfo *vsi;
2642 u64 last_vsi_end_off = 0, sum = 0;
2643 u32 i, meta_needed;
2644
2645 meta_needed = btf_type_vlen(t) * sizeof(*vsi);
2646 if (meta_left < meta_needed) {
2647 btf_verifier_log_basic(env, t,
2648 "meta_left:%u meta_needed:%u",
2649 meta_left, meta_needed);
2650 return -EINVAL;
2651 }
2652
2653 if (!btf_type_vlen(t)) {
2654 btf_verifier_log_type(env, t, "vlen == 0");
2655 return -EINVAL;
2656 }
2657
2658 if (!t->size) {
2659 btf_verifier_log_type(env, t, "size == 0");
2660 return -EINVAL;
2661 }
2662
2663 if (btf_type_kflag(t)) {
2664 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2665 return -EINVAL;
2666 }
2667
2668 if (!t->name_off ||
2669 !btf_name_valid_section(env->btf, t->name_off)) {
2670 btf_verifier_log_type(env, t, "Invalid name");
2671 return -EINVAL;
2672 }
2673
2674 btf_verifier_log_type(env, t, NULL);
2675
2676 for_each_vsi(i, t, vsi) {
2677 /* A var cannot be in type void */
2678 if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) {
2679 btf_verifier_log_vsi(env, t, vsi,
2680 "Invalid type_id");
2681 return -EINVAL;
2682 }
2683
2684 if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) {
2685 btf_verifier_log_vsi(env, t, vsi,
2686 "Invalid offset");
2687 return -EINVAL;
2688 }
2689
2690 if (!vsi->size || vsi->size > t->size) {
2691 btf_verifier_log_vsi(env, t, vsi,
2692 "Invalid size");
2693 return -EINVAL;
2694 }
2695
2696 last_vsi_end_off = vsi->offset + vsi->size;
2697 if (last_vsi_end_off > t->size) {
2698 btf_verifier_log_vsi(env, t, vsi,
2699 "Invalid offset+size");
2700 return -EINVAL;
2701 }
2702
2703 btf_verifier_log_vsi(env, t, vsi, NULL);
2704 sum += vsi->size;
2705 }
2706
2707 if (t->size < sum) {
2708 btf_verifier_log_type(env, t, "Invalid btf_info size");
2709 return -EINVAL;
2710 }
2711
2712 return meta_needed;
2713}
2714
2715static int btf_datasec_resolve(struct btf_verifier_env *env,
2716 const struct resolve_vertex *v)
2717{
2718 const struct btf_var_secinfo *vsi;
2719 struct btf *btf = env->btf;
2720 u16 i;
2721
2722 for_each_vsi_from(i, v->next_member, v->t, vsi) {
2723 u32 var_type_id = vsi->type, type_id, type_size = 0;
2724 const struct btf_type *var_type = btf_type_by_id(env->btf,
2725 var_type_id);
2726 if (!var_type || !btf_type_is_var(var_type)) {
2727 btf_verifier_log_vsi(env, v->t, vsi,
2728 "Not a VAR kind member");
2729 return -EINVAL;
2730 }
2731
2732 if (!env_type_is_resolve_sink(env, var_type) &&
2733 !env_type_is_resolved(env, var_type_id)) {
2734 env_stack_set_next_member(env, i + 1);
2735 return env_stack_push(env, var_type, var_type_id);
2736 }
2737
2738 type_id = var_type->type;
2739 if (!btf_type_id_size(btf, &type_id, &type_size)) {
2740 btf_verifier_log_vsi(env, v->t, vsi, "Invalid type");
2741 return -EINVAL;
2742 }
2743
2744 if (vsi->size < type_size) {
2745 btf_verifier_log_vsi(env, v->t, vsi, "Invalid size");
2746 return -EINVAL;
2747 }
2748 }
2749
2750 env_stack_pop_resolved(env, 0, 0);
2751 return 0;
2752}
2753
2754static void btf_datasec_log(struct btf_verifier_env *env,
2755 const struct btf_type *t)
2756{
2757 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
2758}
2759
2760static void btf_datasec_seq_show(const struct btf *btf,
2761 const struct btf_type *t, u32 type_id,
2762 void *data, u8 bits_offset,
2763 struct seq_file *m)
2764{
2765 const struct btf_var_secinfo *vsi;
2766 const struct btf_type *var;
2767 u32 i;
2768
2769 seq_printf(m, "section (\"%s\") = {", __btf_name_by_offset(btf, t->name_off));
2770 for_each_vsi(i, t, vsi) {
2771 var = btf_type_by_id(btf, vsi->type);
2772 if (i)
2773 seq_puts(m, ",");
2774 btf_type_ops(var)->seq_show(btf, var, vsi->type,
2775 data + vsi->offset, bits_offset, m);
2776 }
2777 seq_puts(m, "}");
2778}
2779
2780static const struct btf_kind_operations datasec_ops = {
2781 .check_meta = btf_datasec_check_meta,
2782 .resolve = btf_datasec_resolve,
2783 .check_member = btf_df_check_member,
2784 .check_kflag_member = btf_df_check_kflag_member,
2785 .log_details = btf_datasec_log,
2786 .seq_show = btf_datasec_seq_show,
2787};
2788
2789static int btf_func_proto_check(struct btf_verifier_env *env,
2790 const struct btf_type *t)
2791{
2792 const struct btf_type *ret_type;
2793 const struct btf_param *args;
2794 const struct btf *btf;
2795 u16 nr_args, i;
2796 int err;
2797
2798 btf = env->btf;
2799 args = (const struct btf_param *)(t + 1);
2800 nr_args = btf_type_vlen(t);
2801
2802 /* Check func return type which could be "void" (t->type == 0) */
2803 if (t->type) {
2804 u32 ret_type_id = t->type;
2805
2806 ret_type = btf_type_by_id(btf, ret_type_id);
2807 if (!ret_type) {
2808 btf_verifier_log_type(env, t, "Invalid return type");
2809 return -EINVAL;
2810 }
2811
2812 if (btf_type_needs_resolve(ret_type) &&
2813 !env_type_is_resolved(env, ret_type_id)) {
2814 err = btf_resolve(env, ret_type, ret_type_id);
2815 if (err)
2816 return err;
2817 }
2818
2819 /* Ensure the return type is a type that has a size */
2820 if (!btf_type_id_size(btf, &ret_type_id, NULL)) {
2821 btf_verifier_log_type(env, t, "Invalid return type");
2822 return -EINVAL;
2823 }
2824 }
2825
2826 if (!nr_args)
2827 return 0;
2828
2829 /* Last func arg type_id could be 0 if it is a vararg */
2830 if (!args[nr_args - 1].type) {
2831 if (args[nr_args - 1].name_off) {
2832 btf_verifier_log_type(env, t, "Invalid arg#%u",
2833 nr_args);
2834 return -EINVAL;
2835 }
2836 nr_args--;
2837 }
2838
2839 err = 0;
2840 for (i = 0; i < nr_args; i++) {
2841 const struct btf_type *arg_type;
2842 u32 arg_type_id;
2843
2844 arg_type_id = args[i].type;
2845 arg_type = btf_type_by_id(btf, arg_type_id);
2846 if (!arg_type) {
2847 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
2848 err = -EINVAL;
2849 break;
2850 }
2851
2852 if (args[i].name_off &&
2853 (!btf_name_offset_valid(btf, args[i].name_off) ||
2854 !btf_name_valid_identifier(btf, args[i].name_off))) {
2855 btf_verifier_log_type(env, t,
2856 "Invalid arg#%u", i + 1);
2857 err = -EINVAL;
2858 break;
2859 }
2860
2861 if (btf_type_needs_resolve(arg_type) &&
2862 !env_type_is_resolved(env, arg_type_id)) {
2863 err = btf_resolve(env, arg_type, arg_type_id);
2864 if (err)
2865 break;
2866 }
2867
2868 if (!btf_type_id_size(btf, &arg_type_id, NULL)) {
2869 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
2870 err = -EINVAL;
2871 break;
2872 }
2873 }
2874
2875 return err;
2876}
2877
2878static int btf_func_check(struct btf_verifier_env *env,
2879 const struct btf_type *t)
2880{
2881 const struct btf_type *proto_type;
2882 const struct btf_param *args;
2883 const struct btf *btf;
2884 u16 nr_args, i;
2885
2886 btf = env->btf;
2887 proto_type = btf_type_by_id(btf, t->type);
2888
2889 if (!proto_type || !btf_type_is_func_proto(proto_type)) {
2890 btf_verifier_log_type(env, t, "Invalid type_id");
2891 return -EINVAL;
2892 }
2893
2894 args = (const struct btf_param *)(proto_type + 1);
2895 nr_args = btf_type_vlen(proto_type);
2896 for (i = 0; i < nr_args; i++) {
2897 if (!args[i].name_off && args[i].type) {
2898 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
2899 return -EINVAL;
2900 }
2901 }
2902
2903 return 0;
2904}
2905
2906static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
2907 [BTF_KIND_INT] = &int_ops,
2908 [BTF_KIND_PTR] = &ptr_ops,
2909 [BTF_KIND_ARRAY] = &array_ops,
2910 [BTF_KIND_STRUCT] = &struct_ops,
2911 [BTF_KIND_UNION] = &struct_ops,
2912 [BTF_KIND_ENUM] = &enum_ops,
2913 [BTF_KIND_FWD] = &fwd_ops,
2914 [BTF_KIND_TYPEDEF] = &modifier_ops,
2915 [BTF_KIND_VOLATILE] = &modifier_ops,
2916 [BTF_KIND_CONST] = &modifier_ops,
2917 [BTF_KIND_RESTRICT] = &modifier_ops,
2918 [BTF_KIND_FUNC] = &func_ops,
2919 [BTF_KIND_FUNC_PROTO] = &func_proto_ops,
2920 [BTF_KIND_VAR] = &var_ops,
2921 [BTF_KIND_DATASEC] = &datasec_ops,
2922};
2923
2924static s32 btf_check_meta(struct btf_verifier_env *env,
2925 const struct btf_type *t,
2926 u32 meta_left)
2927{
2928 u32 saved_meta_left = meta_left;
2929 s32 var_meta_size;
2930
2931 if (meta_left < sizeof(*t)) {
2932 btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
2933 env->log_type_id, meta_left, sizeof(*t));
2934 return -EINVAL;
2935 }
2936 meta_left -= sizeof(*t);
2937
2938 if (t->info & ~BTF_INFO_MASK) {
2939 btf_verifier_log(env, "[%u] Invalid btf_info:%x",
2940 env->log_type_id, t->info);
2941 return -EINVAL;
2942 }
2943
2944 if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
2945 BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
2946 btf_verifier_log(env, "[%u] Invalid kind:%u",
2947 env->log_type_id, BTF_INFO_KIND(t->info));
2948 return -EINVAL;
2949 }
2950
2951 if (!btf_name_offset_valid(env->btf, t->name_off)) {
2952 btf_verifier_log(env, "[%u] Invalid name_offset:%u",
2953 env->log_type_id, t->name_off);
2954 return -EINVAL;
2955 }
2956
2957 var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
2958 if (var_meta_size < 0)
2959 return var_meta_size;
2960
2961 meta_left -= var_meta_size;
2962
2963 return saved_meta_left - meta_left;
2964}
2965
2966static int btf_check_all_metas(struct btf_verifier_env *env)
2967{
2968 struct btf *btf = env->btf;
2969 struct btf_header *hdr;
2970 void *cur, *end;
2971
2972 hdr = &btf->hdr;
2973 cur = btf->nohdr_data + hdr->type_off;
2974 end = cur + hdr->type_len;
2975
2976 env->log_type_id = 1;
2977 while (cur < end) {
2978 struct btf_type *t = cur;
2979 s32 meta_size;
2980
2981 meta_size = btf_check_meta(env, t, end - cur);
2982 if (meta_size < 0)
2983 return meta_size;
2984
2985 btf_add_type(env, t);
2986 cur += meta_size;
2987 env->log_type_id++;
2988 }
2989
2990 return 0;
2991}
2992
2993static bool btf_resolve_valid(struct btf_verifier_env *env,
2994 const struct btf_type *t,
2995 u32 type_id)
2996{
2997 struct btf *btf = env->btf;
2998
2999 if (!env_type_is_resolved(env, type_id))
3000 return false;
3001
3002 if (btf_type_is_struct(t) || btf_type_is_datasec(t))
3003 return !btf->resolved_ids[type_id] &&
3004 !btf->resolved_sizes[type_id];
3005
3006 if (btf_type_is_modifier(t) || btf_type_is_ptr(t) ||
3007 btf_type_is_var(t)) {
3008 t = btf_type_id_resolve(btf, &type_id);
3009 return t &&
3010 !btf_type_is_modifier(t) &&
3011 !btf_type_is_var(t) &&
3012 !btf_type_is_datasec(t);
3013 }
3014
3015 if (btf_type_is_array(t)) {
3016 const struct btf_array *array = btf_type_array(t);
3017 const struct btf_type *elem_type;
3018 u32 elem_type_id = array->type;
3019 u32 elem_size;
3020
3021 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
3022 return elem_type && !btf_type_is_modifier(elem_type) &&
3023 (array->nelems * elem_size ==
3024 btf->resolved_sizes[type_id]);
3025 }
3026
3027 return false;
3028}
3029
3030static int btf_resolve(struct btf_verifier_env *env,
3031 const struct btf_type *t, u32 type_id)
3032{
3033 u32 save_log_type_id = env->log_type_id;
3034 const struct resolve_vertex *v;
3035 int err = 0;
3036
3037 env->resolve_mode = RESOLVE_TBD;
3038 env_stack_push(env, t, type_id);
3039 while (!err && (v = env_stack_peak(env))) {
3040 env->log_type_id = v->type_id;
3041 err = btf_type_ops(v->t)->resolve(env, v);
3042 }
3043
3044 env->log_type_id = type_id;
3045 if (err == -E2BIG) {
3046 btf_verifier_log_type(env, t,
3047 "Exceeded max resolving depth:%u",
3048 MAX_RESOLVE_DEPTH);
3049 } else if (err == -EEXIST) {
3050 btf_verifier_log_type(env, t, "Loop detected");
3051 }
3052
3053 /* Final sanity check */
3054 if (!err && !btf_resolve_valid(env, t, type_id)) {
3055 btf_verifier_log_type(env, t, "Invalid resolve state");
3056 err = -EINVAL;
3057 }
3058
3059 env->log_type_id = save_log_type_id;
3060 return err;
3061}
3062
3063static int btf_check_all_types(struct btf_verifier_env *env)
3064{
3065 struct btf *btf = env->btf;
3066 u32 type_id;
3067 int err;
3068
3069 err = env_resolve_init(env);
3070 if (err)
3071 return err;
3072
3073 env->phase++;
3074 for (type_id = 1; type_id <= btf->nr_types; type_id++) {
3075 const struct btf_type *t = btf_type_by_id(btf, type_id);
3076
3077 env->log_type_id = type_id;
3078 if (btf_type_needs_resolve(t) &&
3079 !env_type_is_resolved(env, type_id)) {
3080 err = btf_resolve(env, t, type_id);
3081 if (err)
3082 return err;
3083 }
3084
3085 if (btf_type_is_func_proto(t)) {
3086 err = btf_func_proto_check(env, t);
3087 if (err)
3088 return err;
3089 }
3090
3091 if (btf_type_is_func(t)) {
3092 err = btf_func_check(env, t);
3093 if (err)
3094 return err;
3095 }
3096 }
3097
3098 return 0;
3099}
3100
3101static int btf_parse_type_sec(struct btf_verifier_env *env)
3102{
3103 const struct btf_header *hdr = &env->btf->hdr;
3104 int err;
3105
3106 /* Type section must align to 4 bytes */
3107 if (hdr->type_off & (sizeof(u32) - 1)) {
3108 btf_verifier_log(env, "Unaligned type_off");
3109 return -EINVAL;
3110 }
3111
3112 if (!hdr->type_len) {
3113 btf_verifier_log(env, "No type found");
3114 return -EINVAL;
3115 }
3116
3117 err = btf_check_all_metas(env);
3118 if (err)
3119 return err;
3120
3121 return btf_check_all_types(env);
3122}
3123
3124static int btf_parse_str_sec(struct btf_verifier_env *env)
3125{
3126 const struct btf_header *hdr;
3127 struct btf *btf = env->btf;
3128 const char *start, *end;
3129
3130 hdr = &btf->hdr;
3131 start = btf->nohdr_data + hdr->str_off;
3132 end = start + hdr->str_len;
3133
3134 if (end != btf->data + btf->data_size) {
3135 btf_verifier_log(env, "String section is not at the end");
3136 return -EINVAL;
3137 }
3138
3139 if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET ||
3140 start[0] || end[-1]) {
3141 btf_verifier_log(env, "Invalid string section");
3142 return -EINVAL;
3143 }
3144
3145 btf->strings = start;
3146
3147 return 0;
3148}
3149
3150static const size_t btf_sec_info_offset[] = {
3151 offsetof(struct btf_header, type_off),
3152 offsetof(struct btf_header, str_off),
3153};
3154
3155static int btf_sec_info_cmp(const void *a, const void *b)
3156{
3157 const struct btf_sec_info *x = a;
3158 const struct btf_sec_info *y = b;
3159
3160 return (int)(x->off - y->off) ? : (int)(x->len - y->len);
3161}
3162
3163static int btf_check_sec_info(struct btf_verifier_env *env,
3164 u32 btf_data_size)
3165{
3166 struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
3167 u32 total, expected_total, i;
3168 const struct btf_header *hdr;
3169 const struct btf *btf;
3170
3171 btf = env->btf;
3172 hdr = &btf->hdr;
3173
3174 /* Populate the secs from hdr */
3175 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
3176 secs[i] = *(struct btf_sec_info *)((void *)hdr +
3177 btf_sec_info_offset[i]);
3178
3179 sort(secs, ARRAY_SIZE(btf_sec_info_offset),
3180 sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
3181
3182 /* Check for gaps and overlap among sections */
3183 total = 0;
3184 expected_total = btf_data_size - hdr->hdr_len;
3185 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
3186 if (expected_total < secs[i].off) {
3187 btf_verifier_log(env, "Invalid section offset");
3188 return -EINVAL;
3189 }
3190 if (total < secs[i].off) {
3191 /* gap */
3192 btf_verifier_log(env, "Unsupported section found");
3193 return -EINVAL;
3194 }
3195 if (total > secs[i].off) {
3196 btf_verifier_log(env, "Section overlap found");
3197 return -EINVAL;
3198 }
3199 if (expected_total - total < secs[i].len) {
3200 btf_verifier_log(env,
3201 "Total section length too long");
3202 return -EINVAL;
3203 }
3204 total += secs[i].len;
3205 }
3206
3207 /* There is data other than hdr and known sections */
3208 if (expected_total != total) {
3209 btf_verifier_log(env, "Unsupported section found");
3210 return -EINVAL;
3211 }
3212
3213 return 0;
3214}
3215
3216static int btf_parse_hdr(struct btf_verifier_env *env)
3217{
3218 u32 hdr_len, hdr_copy, btf_data_size;
3219 const struct btf_header *hdr;
3220 struct btf *btf;
3221 int err;
3222
3223 btf = env->btf;
3224 btf_data_size = btf->data_size;
3225
3226 if (btf_data_size <
3227 offsetof(struct btf_header, hdr_len) + sizeof(hdr->hdr_len)) {
3228 btf_verifier_log(env, "hdr_len not found");
3229 return -EINVAL;
3230 }
3231
3232 hdr = btf->data;
3233 hdr_len = hdr->hdr_len;
3234 if (btf_data_size < hdr_len) {
3235 btf_verifier_log(env, "btf_header not found");
3236 return -EINVAL;
3237 }
3238
3239 /* Ensure the unsupported header fields are zero */
3240 if (hdr_len > sizeof(btf->hdr)) {
3241 u8 *expected_zero = btf->data + sizeof(btf->hdr);
3242 u8 *end = btf->data + hdr_len;
3243
3244 for (; expected_zero < end; expected_zero++) {
3245 if (*expected_zero) {
3246 btf_verifier_log(env, "Unsupported btf_header");
3247 return -E2BIG;
3248 }
3249 }
3250 }
3251
3252 hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
3253 memcpy(&btf->hdr, btf->data, hdr_copy);
3254
3255 hdr = &btf->hdr;
3256
3257 btf_verifier_log_hdr(env, btf_data_size);
3258
3259 if (hdr->magic != BTF_MAGIC) {
3260 btf_verifier_log(env, "Invalid magic");
3261 return -EINVAL;
3262 }
3263
3264 if (hdr->version != BTF_VERSION) {
3265 btf_verifier_log(env, "Unsupported version");
3266 return -ENOTSUPP;
3267 }
3268
3269 if (hdr->flags) {
3270 btf_verifier_log(env, "Unsupported flags");
3271 return -ENOTSUPP;
3272 }
3273
3274 if (btf_data_size == hdr->hdr_len) {
3275 btf_verifier_log(env, "No data");
3276 return -EINVAL;
3277 }
3278
3279 err = btf_check_sec_info(env, btf_data_size);
3280 if (err)
3281 return err;
3282
3283 return 0;
3284}
3285
3286static struct btf *btf_parse(void __user *btf_data, u32 btf_data_size,
3287 u32 log_level, char __user *log_ubuf, u32 log_size)
3288{
3289 struct btf_verifier_env *env = NULL;
3290 struct bpf_verifier_log *log;
3291 struct btf *btf = NULL;
3292 u8 *data;
3293 int err;
3294
3295 if (btf_data_size > BTF_MAX_SIZE)
3296 return ERR_PTR(-E2BIG);
3297
3298 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
3299 if (!env)
3300 return ERR_PTR(-ENOMEM);
3301
3302 log = &env->log;
3303 if (log_level || log_ubuf || log_size) {
3304 /* user requested verbose verifier output
3305 * and supplied buffer to store the verification trace
3306 */
3307 log->level = log_level;
3308 log->ubuf = log_ubuf;
3309 log->len_total = log_size;
3310
3311 /* log attributes have to be sane */
3312 if (log->len_total < 128 || log->len_total > UINT_MAX >> 8 ||
3313 !log->level || !log->ubuf) {
3314 err = -EINVAL;
3315 goto errout;
3316 }
3317 }
3318
3319 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
3320 if (!btf) {
3321 err = -ENOMEM;
3322 goto errout;
3323 }
3324 env->btf = btf;
3325
3326 data = kvmalloc(btf_data_size, GFP_KERNEL | __GFP_NOWARN);
3327 if (!data) {
3328 err = -ENOMEM;
3329 goto errout;
3330 }
3331
3332 btf->data = data;
3333 btf->data_size = btf_data_size;
3334
3335 if (copy_from_user(data, btf_data, btf_data_size)) {
3336 err = -EFAULT;
3337 goto errout;
3338 }
3339
3340 err = btf_parse_hdr(env);
3341 if (err)
3342 goto errout;
3343
3344 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
3345
3346 err = btf_parse_str_sec(env);
3347 if (err)
3348 goto errout;
3349
3350 err = btf_parse_type_sec(env);
3351 if (err)
3352 goto errout;
3353
3354 if (log->level && bpf_verifier_log_full(log)) {
3355 err = -ENOSPC;
3356 goto errout;
3357 }
3358
3359 btf_verifier_env_free(env);
3360 refcount_set(&btf->refcnt, 1);
3361 return btf;
3362
3363errout:
3364 btf_verifier_env_free(env);
3365 if (btf)
3366 btf_free(btf);
3367 return ERR_PTR(err);
3368}
3369
3370void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
3371 struct seq_file *m)
3372{
3373 const struct btf_type *t = btf_type_by_id(btf, type_id);
3374
3375 btf_type_ops(t)->seq_show(btf, t, type_id, obj, 0, m);
3376}
3377
3378#ifdef CONFIG_PROC_FS
3379static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp)
3380{
3381 const struct btf *btf = filp->private_data;
3382
3383 seq_printf(m, "btf_id:\t%u\n", btf->id);
3384}
3385#endif
3386
3387static int btf_release(struct inode *inode, struct file *filp)
3388{
3389 btf_put(filp->private_data);
3390 return 0;
3391}
3392
3393const struct file_operations btf_fops = {
3394#ifdef CONFIG_PROC_FS
3395 .show_fdinfo = bpf_btf_show_fdinfo,
3396#endif
3397 .release = btf_release,
3398};
3399
3400static int __btf_new_fd(struct btf *btf)
3401{
3402 return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
3403}
3404
3405int btf_new_fd(const union bpf_attr *attr)
3406{
3407 struct btf *btf;
3408 int ret;
3409
3410 btf = btf_parse(u64_to_user_ptr(attr->btf),
3411 attr->btf_size, attr->btf_log_level,
3412 u64_to_user_ptr(attr->btf_log_buf),
3413 attr->btf_log_size);
3414 if (IS_ERR(btf))
3415 return PTR_ERR(btf);
3416
3417 ret = btf_alloc_id(btf);
3418 if (ret) {
3419 btf_free(btf);
3420 return ret;
3421 }
3422
3423 /*
3424 * The BTF ID is published to the userspace.
3425 * All BTF free must go through call_rcu() from
3426 * now on (i.e. free by calling btf_put()).
3427 */
3428
3429 ret = __btf_new_fd(btf);
3430 if (ret < 0)
3431 btf_put(btf);
3432
3433 return ret;
3434}
3435
3436struct btf *btf_get_by_fd(int fd)
3437{
3438 struct btf *btf;
3439 struct fd f;
3440
3441 f = fdget(fd);
3442
3443 if (!f.file)
3444 return ERR_PTR(-EBADF);
3445
3446 if (f.file->f_op != &btf_fops) {
3447 fdput(f);
3448 return ERR_PTR(-EINVAL);
3449 }
3450
3451 btf = f.file->private_data;
3452 refcount_inc(&btf->refcnt);
3453 fdput(f);
3454
3455 return btf;
3456}
3457
3458int btf_get_info_by_fd(const struct btf *btf,
3459 const union bpf_attr *attr,
3460 union bpf_attr __user *uattr)
3461{
3462 struct bpf_btf_info __user *uinfo;
3463 struct bpf_btf_info info = {};
3464 u32 info_copy, btf_copy;
3465 void __user *ubtf;
3466 u32 uinfo_len;
3467
3468 uinfo = u64_to_user_ptr(attr->info.info);
3469 uinfo_len = attr->info.info_len;
3470
3471 info_copy = min_t(u32, uinfo_len, sizeof(info));
3472 if (copy_from_user(&info, uinfo, info_copy))
3473 return -EFAULT;
3474
3475 info.id = btf->id;
3476 ubtf = u64_to_user_ptr(info.btf);
3477 btf_copy = min_t(u32, btf->data_size, info.btf_size);
3478 if (copy_to_user(ubtf, btf->data, btf_copy))
3479 return -EFAULT;
3480 info.btf_size = btf->data_size;
3481
3482 if (copy_to_user(uinfo, &info, info_copy) ||
3483 put_user(info_copy, &uattr->info.info_len))
3484 return -EFAULT;
3485
3486 return 0;
3487}
3488
3489int btf_get_fd_by_id(u32 id)
3490{
3491 struct btf *btf;
3492 int fd;
3493
3494 rcu_read_lock();
3495 btf = idr_find(&btf_idr, id);
3496 if (!btf || !refcount_inc_not_zero(&btf->refcnt))
3497 btf = ERR_PTR(-ENOENT);
3498 rcu_read_unlock();
3499
3500 if (IS_ERR(btf))
3501 return PTR_ERR(btf);
3502
3503 fd = __btf_new_fd(btf);
3504 if (fd < 0)
3505 btf_put(btf);
3506
3507 return fd;
3508}
3509
3510u32 btf_id(const struct btf *btf)
3511{
3512 return btf->id;
3513}
1/* SPDX-License-Identifier: GPL-2.0 */
2/* Copyright (c) 2018 Facebook */
3
4#include <uapi/linux/btf.h>
5#include <uapi/linux/bpf.h>
6#include <uapi/linux/bpf_perf_event.h>
7#include <uapi/linux/types.h>
8#include <linux/seq_file.h>
9#include <linux/compiler.h>
10#include <linux/ctype.h>
11#include <linux/errno.h>
12#include <linux/slab.h>
13#include <linux/anon_inodes.h>
14#include <linux/file.h>
15#include <linux/uaccess.h>
16#include <linux/kernel.h>
17#include <linux/idr.h>
18#include <linux/sort.h>
19#include <linux/bpf_verifier.h>
20#include <linux/btf.h>
21#include <linux/btf_ids.h>
22#include <linux/skmsg.h>
23#include <linux/perf_event.h>
24#include <linux/bsearch.h>
25#include <linux/kobject.h>
26#include <linux/sysfs.h>
27#include <net/sock.h>
28
29/* BTF (BPF Type Format) is the meta data format which describes
30 * the data types of BPF program/map. Hence, it basically focus
31 * on the C programming language which the modern BPF is primary
32 * using.
33 *
34 * ELF Section:
35 * ~~~~~~~~~~~
36 * The BTF data is stored under the ".BTF" ELF section
37 *
38 * struct btf_type:
39 * ~~~~~~~~~~~~~~~
40 * Each 'struct btf_type' object describes a C data type.
41 * Depending on the type it is describing, a 'struct btf_type'
42 * object may be followed by more data. F.e.
43 * To describe an array, 'struct btf_type' is followed by
44 * 'struct btf_array'.
45 *
46 * 'struct btf_type' and any extra data following it are
47 * 4 bytes aligned.
48 *
49 * Type section:
50 * ~~~~~~~~~~~~~
51 * The BTF type section contains a list of 'struct btf_type' objects.
52 * Each one describes a C type. Recall from the above section
53 * that a 'struct btf_type' object could be immediately followed by extra
54 * data in order to describe some particular C types.
55 *
56 * type_id:
57 * ~~~~~~~
58 * Each btf_type object is identified by a type_id. The type_id
59 * is implicitly implied by the location of the btf_type object in
60 * the BTF type section. The first one has type_id 1. The second
61 * one has type_id 2...etc. Hence, an earlier btf_type has
62 * a smaller type_id.
63 *
64 * A btf_type object may refer to another btf_type object by using
65 * type_id (i.e. the "type" in the "struct btf_type").
66 *
67 * NOTE that we cannot assume any reference-order.
68 * A btf_type object can refer to an earlier btf_type object
69 * but it can also refer to a later btf_type object.
70 *
71 * For example, to describe "const void *". A btf_type
72 * object describing "const" may refer to another btf_type
73 * object describing "void *". This type-reference is done
74 * by specifying type_id:
75 *
76 * [1] CONST (anon) type_id=2
77 * [2] PTR (anon) type_id=0
78 *
79 * The above is the btf_verifier debug log:
80 * - Each line started with "[?]" is a btf_type object
81 * - [?] is the type_id of the btf_type object.
82 * - CONST/PTR is the BTF_KIND_XXX
83 * - "(anon)" is the name of the type. It just
84 * happens that CONST and PTR has no name.
85 * - type_id=XXX is the 'u32 type' in btf_type
86 *
87 * NOTE: "void" has type_id 0
88 *
89 * String section:
90 * ~~~~~~~~~~~~~~
91 * The BTF string section contains the names used by the type section.
92 * Each string is referred by an "offset" from the beginning of the
93 * string section.
94 *
95 * Each string is '\0' terminated.
96 *
97 * The first character in the string section must be '\0'
98 * which is used to mean 'anonymous'. Some btf_type may not
99 * have a name.
100 */
101
102/* BTF verification:
103 *
104 * To verify BTF data, two passes are needed.
105 *
106 * Pass #1
107 * ~~~~~~~
108 * The first pass is to collect all btf_type objects to
109 * an array: "btf->types".
110 *
111 * Depending on the C type that a btf_type is describing,
112 * a btf_type may be followed by extra data. We don't know
113 * how many btf_type is there, and more importantly we don't
114 * know where each btf_type is located in the type section.
115 *
116 * Without knowing the location of each type_id, most verifications
117 * cannot be done. e.g. an earlier btf_type may refer to a later
118 * btf_type (recall the "const void *" above), so we cannot
119 * check this type-reference in the first pass.
120 *
121 * In the first pass, it still does some verifications (e.g.
122 * checking the name is a valid offset to the string section).
123 *
124 * Pass #2
125 * ~~~~~~~
126 * The main focus is to resolve a btf_type that is referring
127 * to another type.
128 *
129 * We have to ensure the referring type:
130 * 1) does exist in the BTF (i.e. in btf->types[])
131 * 2) does not cause a loop:
132 * struct A {
133 * struct B b;
134 * };
135 *
136 * struct B {
137 * struct A a;
138 * };
139 *
140 * btf_type_needs_resolve() decides if a btf_type needs
141 * to be resolved.
142 *
143 * The needs_resolve type implements the "resolve()" ops which
144 * essentially does a DFS and detects backedge.
145 *
146 * During resolve (or DFS), different C types have different
147 * "RESOLVED" conditions.
148 *
149 * When resolving a BTF_KIND_STRUCT, we need to resolve all its
150 * members because a member is always referring to another
151 * type. A struct's member can be treated as "RESOLVED" if
152 * it is referring to a BTF_KIND_PTR. Otherwise, the
153 * following valid C struct would be rejected:
154 *
155 * struct A {
156 * int m;
157 * struct A *a;
158 * };
159 *
160 * When resolving a BTF_KIND_PTR, it needs to keep resolving if
161 * it is referring to another BTF_KIND_PTR. Otherwise, we cannot
162 * detect a pointer loop, e.g.:
163 * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR +
164 * ^ |
165 * +-----------------------------------------+
166 *
167 */
168
169#define BITS_PER_U128 (sizeof(u64) * BITS_PER_BYTE * 2)
170#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
171#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
172#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
173#define BITS_ROUNDUP_BYTES(bits) \
174 (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
175
176#define BTF_INFO_MASK 0x9f00ffff
177#define BTF_INT_MASK 0x0fffffff
178#define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
179#define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
180
181/* 16MB for 64k structs and each has 16 members and
182 * a few MB spaces for the string section.
183 * The hard limit is S32_MAX.
184 */
185#define BTF_MAX_SIZE (16 * 1024 * 1024)
186
187#define for_each_member_from(i, from, struct_type, member) \
188 for (i = from, member = btf_type_member(struct_type) + from; \
189 i < btf_type_vlen(struct_type); \
190 i++, member++)
191
192#define for_each_vsi_from(i, from, struct_type, member) \
193 for (i = from, member = btf_type_var_secinfo(struct_type) + from; \
194 i < btf_type_vlen(struct_type); \
195 i++, member++)
196
197DEFINE_IDR(btf_idr);
198DEFINE_SPINLOCK(btf_idr_lock);
199
200struct btf {
201 void *data;
202 struct btf_type **types;
203 u32 *resolved_ids;
204 u32 *resolved_sizes;
205 const char *strings;
206 void *nohdr_data;
207 struct btf_header hdr;
208 u32 nr_types; /* includes VOID for base BTF */
209 u32 types_size;
210 u32 data_size;
211 refcount_t refcnt;
212 u32 id;
213 struct rcu_head rcu;
214
215 /* split BTF support */
216 struct btf *base_btf;
217 u32 start_id; /* first type ID in this BTF (0 for base BTF) */
218 u32 start_str_off; /* first string offset (0 for base BTF) */
219 char name[MODULE_NAME_LEN];
220 bool kernel_btf;
221};
222
223enum verifier_phase {
224 CHECK_META,
225 CHECK_TYPE,
226};
227
228struct resolve_vertex {
229 const struct btf_type *t;
230 u32 type_id;
231 u16 next_member;
232};
233
234enum visit_state {
235 NOT_VISITED,
236 VISITED,
237 RESOLVED,
238};
239
240enum resolve_mode {
241 RESOLVE_TBD, /* To Be Determined */
242 RESOLVE_PTR, /* Resolving for Pointer */
243 RESOLVE_STRUCT_OR_ARRAY, /* Resolving for struct/union
244 * or array
245 */
246};
247
248#define MAX_RESOLVE_DEPTH 32
249
250struct btf_sec_info {
251 u32 off;
252 u32 len;
253};
254
255struct btf_verifier_env {
256 struct btf *btf;
257 u8 *visit_states;
258 struct resolve_vertex stack[MAX_RESOLVE_DEPTH];
259 struct bpf_verifier_log log;
260 u32 log_type_id;
261 u32 top_stack;
262 enum verifier_phase phase;
263 enum resolve_mode resolve_mode;
264};
265
266static const char * const btf_kind_str[NR_BTF_KINDS] = {
267 [BTF_KIND_UNKN] = "UNKNOWN",
268 [BTF_KIND_INT] = "INT",
269 [BTF_KIND_PTR] = "PTR",
270 [BTF_KIND_ARRAY] = "ARRAY",
271 [BTF_KIND_STRUCT] = "STRUCT",
272 [BTF_KIND_UNION] = "UNION",
273 [BTF_KIND_ENUM] = "ENUM",
274 [BTF_KIND_FWD] = "FWD",
275 [BTF_KIND_TYPEDEF] = "TYPEDEF",
276 [BTF_KIND_VOLATILE] = "VOLATILE",
277 [BTF_KIND_CONST] = "CONST",
278 [BTF_KIND_RESTRICT] = "RESTRICT",
279 [BTF_KIND_FUNC] = "FUNC",
280 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
281 [BTF_KIND_VAR] = "VAR",
282 [BTF_KIND_DATASEC] = "DATASEC",
283 [BTF_KIND_FLOAT] = "FLOAT",
284};
285
286const char *btf_type_str(const struct btf_type *t)
287{
288 return btf_kind_str[BTF_INFO_KIND(t->info)];
289}
290
291/* Chunk size we use in safe copy of data to be shown. */
292#define BTF_SHOW_OBJ_SAFE_SIZE 32
293
294/*
295 * This is the maximum size of a base type value (equivalent to a
296 * 128-bit int); if we are at the end of our safe buffer and have
297 * less than 16 bytes space we can't be assured of being able
298 * to copy the next type safely, so in such cases we will initiate
299 * a new copy.
300 */
301#define BTF_SHOW_OBJ_BASE_TYPE_SIZE 16
302
303/* Type name size */
304#define BTF_SHOW_NAME_SIZE 80
305
306/*
307 * Common data to all BTF show operations. Private show functions can add
308 * their own data to a structure containing a struct btf_show and consult it
309 * in the show callback. See btf_type_show() below.
310 *
311 * One challenge with showing nested data is we want to skip 0-valued
312 * data, but in order to figure out whether a nested object is all zeros
313 * we need to walk through it. As a result, we need to make two passes
314 * when handling structs, unions and arrays; the first path simply looks
315 * for nonzero data, while the second actually does the display. The first
316 * pass is signalled by show->state.depth_check being set, and if we
317 * encounter a non-zero value we set show->state.depth_to_show to
318 * the depth at which we encountered it. When we have completed the
319 * first pass, we will know if anything needs to be displayed if
320 * depth_to_show > depth. See btf_[struct,array]_show() for the
321 * implementation of this.
322 *
323 * Another problem is we want to ensure the data for display is safe to
324 * access. To support this, the anonymous "struct {} obj" tracks the data
325 * object and our safe copy of it. We copy portions of the data needed
326 * to the object "copy" buffer, but because its size is limited to
327 * BTF_SHOW_OBJ_COPY_LEN bytes, multiple copies may be required as we
328 * traverse larger objects for display.
329 *
330 * The various data type show functions all start with a call to
331 * btf_show_start_type() which returns a pointer to the safe copy
332 * of the data needed (or if BTF_SHOW_UNSAFE is specified, to the
333 * raw data itself). btf_show_obj_safe() is responsible for
334 * using copy_from_kernel_nofault() to update the safe data if necessary
335 * as we traverse the object's data. skbuff-like semantics are
336 * used:
337 *
338 * - obj.head points to the start of the toplevel object for display
339 * - obj.size is the size of the toplevel object
340 * - obj.data points to the current point in the original data at
341 * which our safe data starts. obj.data will advance as we copy
342 * portions of the data.
343 *
344 * In most cases a single copy will suffice, but larger data structures
345 * such as "struct task_struct" will require many copies. The logic in
346 * btf_show_obj_safe() handles the logic that determines if a new
347 * copy_from_kernel_nofault() is needed.
348 */
349struct btf_show {
350 u64 flags;
351 void *target; /* target of show operation (seq file, buffer) */
352 void (*showfn)(struct btf_show *show, const char *fmt, va_list args);
353 const struct btf *btf;
354 /* below are used during iteration */
355 struct {
356 u8 depth;
357 u8 depth_to_show;
358 u8 depth_check;
359 u8 array_member:1,
360 array_terminated:1;
361 u16 array_encoding;
362 u32 type_id;
363 int status; /* non-zero for error */
364 const struct btf_type *type;
365 const struct btf_member *member;
366 char name[BTF_SHOW_NAME_SIZE]; /* space for member name/type */
367 } state;
368 struct {
369 u32 size;
370 void *head;
371 void *data;
372 u8 safe[BTF_SHOW_OBJ_SAFE_SIZE];
373 } obj;
374};
375
376struct btf_kind_operations {
377 s32 (*check_meta)(struct btf_verifier_env *env,
378 const struct btf_type *t,
379 u32 meta_left);
380 int (*resolve)(struct btf_verifier_env *env,
381 const struct resolve_vertex *v);
382 int (*check_member)(struct btf_verifier_env *env,
383 const struct btf_type *struct_type,
384 const struct btf_member *member,
385 const struct btf_type *member_type);
386 int (*check_kflag_member)(struct btf_verifier_env *env,
387 const struct btf_type *struct_type,
388 const struct btf_member *member,
389 const struct btf_type *member_type);
390 void (*log_details)(struct btf_verifier_env *env,
391 const struct btf_type *t);
392 void (*show)(const struct btf *btf, const struct btf_type *t,
393 u32 type_id, void *data, u8 bits_offsets,
394 struct btf_show *show);
395};
396
397static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS];
398static struct btf_type btf_void;
399
400static int btf_resolve(struct btf_verifier_env *env,
401 const struct btf_type *t, u32 type_id);
402
403static bool btf_type_is_modifier(const struct btf_type *t)
404{
405 /* Some of them is not strictly a C modifier
406 * but they are grouped into the same bucket
407 * for BTF concern:
408 * A type (t) that refers to another
409 * type through t->type AND its size cannot
410 * be determined without following the t->type.
411 *
412 * ptr does not fall into this bucket
413 * because its size is always sizeof(void *).
414 */
415 switch (BTF_INFO_KIND(t->info)) {
416 case BTF_KIND_TYPEDEF:
417 case BTF_KIND_VOLATILE:
418 case BTF_KIND_CONST:
419 case BTF_KIND_RESTRICT:
420 return true;
421 }
422
423 return false;
424}
425
426bool btf_type_is_void(const struct btf_type *t)
427{
428 return t == &btf_void;
429}
430
431static bool btf_type_is_fwd(const struct btf_type *t)
432{
433 return BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
434}
435
436static bool btf_type_nosize(const struct btf_type *t)
437{
438 return btf_type_is_void(t) || btf_type_is_fwd(t) ||
439 btf_type_is_func(t) || btf_type_is_func_proto(t);
440}
441
442static bool btf_type_nosize_or_null(const struct btf_type *t)
443{
444 return !t || btf_type_nosize(t);
445}
446
447static bool __btf_type_is_struct(const struct btf_type *t)
448{
449 return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT;
450}
451
452static bool btf_type_is_array(const struct btf_type *t)
453{
454 return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY;
455}
456
457static bool btf_type_is_datasec(const struct btf_type *t)
458{
459 return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
460}
461
462u32 btf_nr_types(const struct btf *btf)
463{
464 u32 total = 0;
465
466 while (btf) {
467 total += btf->nr_types;
468 btf = btf->base_btf;
469 }
470
471 return total;
472}
473
474s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind)
475{
476 const struct btf_type *t;
477 const char *tname;
478 u32 i, total;
479
480 total = btf_nr_types(btf);
481 for (i = 1; i < total; i++) {
482 t = btf_type_by_id(btf, i);
483 if (BTF_INFO_KIND(t->info) != kind)
484 continue;
485
486 tname = btf_name_by_offset(btf, t->name_off);
487 if (!strcmp(tname, name))
488 return i;
489 }
490
491 return -ENOENT;
492}
493
494const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
495 u32 id, u32 *res_id)
496{
497 const struct btf_type *t = btf_type_by_id(btf, id);
498
499 while (btf_type_is_modifier(t)) {
500 id = t->type;
501 t = btf_type_by_id(btf, t->type);
502 }
503
504 if (res_id)
505 *res_id = id;
506
507 return t;
508}
509
510const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
511 u32 id, u32 *res_id)
512{
513 const struct btf_type *t;
514
515 t = btf_type_skip_modifiers(btf, id, NULL);
516 if (!btf_type_is_ptr(t))
517 return NULL;
518
519 return btf_type_skip_modifiers(btf, t->type, res_id);
520}
521
522const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
523 u32 id, u32 *res_id)
524{
525 const struct btf_type *ptype;
526
527 ptype = btf_type_resolve_ptr(btf, id, res_id);
528 if (ptype && btf_type_is_func_proto(ptype))
529 return ptype;
530
531 return NULL;
532}
533
534/* Types that act only as a source, not sink or intermediate
535 * type when resolving.
536 */
537static bool btf_type_is_resolve_source_only(const struct btf_type *t)
538{
539 return btf_type_is_var(t) ||
540 btf_type_is_datasec(t);
541}
542
543/* What types need to be resolved?
544 *
545 * btf_type_is_modifier() is an obvious one.
546 *
547 * btf_type_is_struct() because its member refers to
548 * another type (through member->type).
549 *
550 * btf_type_is_var() because the variable refers to
551 * another type. btf_type_is_datasec() holds multiple
552 * btf_type_is_var() types that need resolving.
553 *
554 * btf_type_is_array() because its element (array->type)
555 * refers to another type. Array can be thought of a
556 * special case of struct while array just has the same
557 * member-type repeated by array->nelems of times.
558 */
559static bool btf_type_needs_resolve(const struct btf_type *t)
560{
561 return btf_type_is_modifier(t) ||
562 btf_type_is_ptr(t) ||
563 btf_type_is_struct(t) ||
564 btf_type_is_array(t) ||
565 btf_type_is_var(t) ||
566 btf_type_is_datasec(t);
567}
568
569/* t->size can be used */
570static bool btf_type_has_size(const struct btf_type *t)
571{
572 switch (BTF_INFO_KIND(t->info)) {
573 case BTF_KIND_INT:
574 case BTF_KIND_STRUCT:
575 case BTF_KIND_UNION:
576 case BTF_KIND_ENUM:
577 case BTF_KIND_DATASEC:
578 case BTF_KIND_FLOAT:
579 return true;
580 }
581
582 return false;
583}
584
585static const char *btf_int_encoding_str(u8 encoding)
586{
587 if (encoding == 0)
588 return "(none)";
589 else if (encoding == BTF_INT_SIGNED)
590 return "SIGNED";
591 else if (encoding == BTF_INT_CHAR)
592 return "CHAR";
593 else if (encoding == BTF_INT_BOOL)
594 return "BOOL";
595 else
596 return "UNKN";
597}
598
599static u32 btf_type_int(const struct btf_type *t)
600{
601 return *(u32 *)(t + 1);
602}
603
604static const struct btf_array *btf_type_array(const struct btf_type *t)
605{
606 return (const struct btf_array *)(t + 1);
607}
608
609static const struct btf_enum *btf_type_enum(const struct btf_type *t)
610{
611 return (const struct btf_enum *)(t + 1);
612}
613
614static const struct btf_var *btf_type_var(const struct btf_type *t)
615{
616 return (const struct btf_var *)(t + 1);
617}
618
619static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
620{
621 return kind_ops[BTF_INFO_KIND(t->info)];
622}
623
624static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
625{
626 if (!BTF_STR_OFFSET_VALID(offset))
627 return false;
628
629 while (offset < btf->start_str_off)
630 btf = btf->base_btf;
631
632 offset -= btf->start_str_off;
633 return offset < btf->hdr.str_len;
634}
635
636static bool __btf_name_char_ok(char c, bool first, bool dot_ok)
637{
638 if ((first ? !isalpha(c) :
639 !isalnum(c)) &&
640 c != '_' &&
641 ((c == '.' && !dot_ok) ||
642 c != '.'))
643 return false;
644 return true;
645}
646
647static const char *btf_str_by_offset(const struct btf *btf, u32 offset)
648{
649 while (offset < btf->start_str_off)
650 btf = btf->base_btf;
651
652 offset -= btf->start_str_off;
653 if (offset < btf->hdr.str_len)
654 return &btf->strings[offset];
655
656 return NULL;
657}
658
659static bool __btf_name_valid(const struct btf *btf, u32 offset, bool dot_ok)
660{
661 /* offset must be valid */
662 const char *src = btf_str_by_offset(btf, offset);
663 const char *src_limit;
664
665 if (!__btf_name_char_ok(*src, true, dot_ok))
666 return false;
667
668 /* set a limit on identifier length */
669 src_limit = src + KSYM_NAME_LEN;
670 src++;
671 while (*src && src < src_limit) {
672 if (!__btf_name_char_ok(*src, false, dot_ok))
673 return false;
674 src++;
675 }
676
677 return !*src;
678}
679
680/* Only C-style identifier is permitted. This can be relaxed if
681 * necessary.
682 */
683static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
684{
685 return __btf_name_valid(btf, offset, false);
686}
687
688static bool btf_name_valid_section(const struct btf *btf, u32 offset)
689{
690 return __btf_name_valid(btf, offset, true);
691}
692
693static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
694{
695 const char *name;
696
697 if (!offset)
698 return "(anon)";
699
700 name = btf_str_by_offset(btf, offset);
701 return name ?: "(invalid-name-offset)";
702}
703
704const char *btf_name_by_offset(const struct btf *btf, u32 offset)
705{
706 return btf_str_by_offset(btf, offset);
707}
708
709const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
710{
711 while (type_id < btf->start_id)
712 btf = btf->base_btf;
713
714 type_id -= btf->start_id;
715 if (type_id >= btf->nr_types)
716 return NULL;
717 return btf->types[type_id];
718}
719
720/*
721 * Regular int is not a bit field and it must be either
722 * u8/u16/u32/u64 or __int128.
723 */
724static bool btf_type_int_is_regular(const struct btf_type *t)
725{
726 u8 nr_bits, nr_bytes;
727 u32 int_data;
728
729 int_data = btf_type_int(t);
730 nr_bits = BTF_INT_BITS(int_data);
731 nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
732 if (BITS_PER_BYTE_MASKED(nr_bits) ||
733 BTF_INT_OFFSET(int_data) ||
734 (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) &&
735 nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64) &&
736 nr_bytes != (2 * sizeof(u64)))) {
737 return false;
738 }
739
740 return true;
741}
742
743/*
744 * Check that given struct member is a regular int with expected
745 * offset and size.
746 */
747bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
748 const struct btf_member *m,
749 u32 expected_offset, u32 expected_size)
750{
751 const struct btf_type *t;
752 u32 id, int_data;
753 u8 nr_bits;
754
755 id = m->type;
756 t = btf_type_id_size(btf, &id, NULL);
757 if (!t || !btf_type_is_int(t))
758 return false;
759
760 int_data = btf_type_int(t);
761 nr_bits = BTF_INT_BITS(int_data);
762 if (btf_type_kflag(s)) {
763 u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset);
764 u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset);
765
766 /* if kflag set, int should be a regular int and
767 * bit offset should be at byte boundary.
768 */
769 return !bitfield_size &&
770 BITS_ROUNDUP_BYTES(bit_offset) == expected_offset &&
771 BITS_ROUNDUP_BYTES(nr_bits) == expected_size;
772 }
773
774 if (BTF_INT_OFFSET(int_data) ||
775 BITS_PER_BYTE_MASKED(m->offset) ||
776 BITS_ROUNDUP_BYTES(m->offset) != expected_offset ||
777 BITS_PER_BYTE_MASKED(nr_bits) ||
778 BITS_ROUNDUP_BYTES(nr_bits) != expected_size)
779 return false;
780
781 return true;
782}
783
784/* Similar to btf_type_skip_modifiers() but does not skip typedefs. */
785static const struct btf_type *btf_type_skip_qualifiers(const struct btf *btf,
786 u32 id)
787{
788 const struct btf_type *t = btf_type_by_id(btf, id);
789
790 while (btf_type_is_modifier(t) &&
791 BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) {
792 t = btf_type_by_id(btf, t->type);
793 }
794
795 return t;
796}
797
798#define BTF_SHOW_MAX_ITER 10
799
800#define BTF_KIND_BIT(kind) (1ULL << kind)
801
802/*
803 * Populate show->state.name with type name information.
804 * Format of type name is
805 *
806 * [.member_name = ] (type_name)
807 */
808static const char *btf_show_name(struct btf_show *show)
809{
810 /* BTF_MAX_ITER array suffixes "[]" */
811 const char *array_suffixes = "[][][][][][][][][][]";
812 const char *array_suffix = &array_suffixes[strlen(array_suffixes)];
813 /* BTF_MAX_ITER pointer suffixes "*" */
814 const char *ptr_suffixes = "**********";
815 const char *ptr_suffix = &ptr_suffixes[strlen(ptr_suffixes)];
816 const char *name = NULL, *prefix = "", *parens = "";
817 const struct btf_member *m = show->state.member;
818 const struct btf_type *t = show->state.type;
819 const struct btf_array *array;
820 u32 id = show->state.type_id;
821 const char *member = NULL;
822 bool show_member = false;
823 u64 kinds = 0;
824 int i;
825
826 show->state.name[0] = '\0';
827
828 /*
829 * Don't show type name if we're showing an array member;
830 * in that case we show the array type so don't need to repeat
831 * ourselves for each member.
832 */
833 if (show->state.array_member)
834 return "";
835
836 /* Retrieve member name, if any. */
837 if (m) {
838 member = btf_name_by_offset(show->btf, m->name_off);
839 show_member = strlen(member) > 0;
840 id = m->type;
841 }
842
843 /*
844 * Start with type_id, as we have resolved the struct btf_type *
845 * via btf_modifier_show() past the parent typedef to the child
846 * struct, int etc it is defined as. In such cases, the type_id
847 * still represents the starting type while the struct btf_type *
848 * in our show->state points at the resolved type of the typedef.
849 */
850 t = btf_type_by_id(show->btf, id);
851 if (!t)
852 return "";
853
854 /*
855 * The goal here is to build up the right number of pointer and
856 * array suffixes while ensuring the type name for a typedef
857 * is represented. Along the way we accumulate a list of
858 * BTF kinds we have encountered, since these will inform later
859 * display; for example, pointer types will not require an
860 * opening "{" for struct, we will just display the pointer value.
861 *
862 * We also want to accumulate the right number of pointer or array
863 * indices in the format string while iterating until we get to
864 * the typedef/pointee/array member target type.
865 *
866 * We start by pointing at the end of pointer and array suffix
867 * strings; as we accumulate pointers and arrays we move the pointer
868 * or array string backwards so it will show the expected number of
869 * '*' or '[]' for the type. BTF_SHOW_MAX_ITER of nesting of pointers
870 * and/or arrays and typedefs are supported as a precaution.
871 *
872 * We also want to get typedef name while proceeding to resolve
873 * type it points to so that we can add parentheses if it is a
874 * "typedef struct" etc.
875 */
876 for (i = 0; i < BTF_SHOW_MAX_ITER; i++) {
877
878 switch (BTF_INFO_KIND(t->info)) {
879 case BTF_KIND_TYPEDEF:
880 if (!name)
881 name = btf_name_by_offset(show->btf,
882 t->name_off);
883 kinds |= BTF_KIND_BIT(BTF_KIND_TYPEDEF);
884 id = t->type;
885 break;
886 case BTF_KIND_ARRAY:
887 kinds |= BTF_KIND_BIT(BTF_KIND_ARRAY);
888 parens = "[";
889 if (!t)
890 return "";
891 array = btf_type_array(t);
892 if (array_suffix > array_suffixes)
893 array_suffix -= 2;
894 id = array->type;
895 break;
896 case BTF_KIND_PTR:
897 kinds |= BTF_KIND_BIT(BTF_KIND_PTR);
898 if (ptr_suffix > ptr_suffixes)
899 ptr_suffix -= 1;
900 id = t->type;
901 break;
902 default:
903 id = 0;
904 break;
905 }
906 if (!id)
907 break;
908 t = btf_type_skip_qualifiers(show->btf, id);
909 }
910 /* We may not be able to represent this type; bail to be safe */
911 if (i == BTF_SHOW_MAX_ITER)
912 return "";
913
914 if (!name)
915 name = btf_name_by_offset(show->btf, t->name_off);
916
917 switch (BTF_INFO_KIND(t->info)) {
918 case BTF_KIND_STRUCT:
919 case BTF_KIND_UNION:
920 prefix = BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT ?
921 "struct" : "union";
922 /* if it's an array of struct/union, parens is already set */
923 if (!(kinds & (BTF_KIND_BIT(BTF_KIND_ARRAY))))
924 parens = "{";
925 break;
926 case BTF_KIND_ENUM:
927 prefix = "enum";
928 break;
929 default:
930 break;
931 }
932
933 /* pointer does not require parens */
934 if (kinds & BTF_KIND_BIT(BTF_KIND_PTR))
935 parens = "";
936 /* typedef does not require struct/union/enum prefix */
937 if (kinds & BTF_KIND_BIT(BTF_KIND_TYPEDEF))
938 prefix = "";
939
940 if (!name)
941 name = "";
942
943 /* Even if we don't want type name info, we want parentheses etc */
944 if (show->flags & BTF_SHOW_NONAME)
945 snprintf(show->state.name, sizeof(show->state.name), "%s",
946 parens);
947 else
948 snprintf(show->state.name, sizeof(show->state.name),
949 "%s%s%s(%s%s%s%s%s%s)%s",
950 /* first 3 strings comprise ".member = " */
951 show_member ? "." : "",
952 show_member ? member : "",
953 show_member ? " = " : "",
954 /* ...next is our prefix (struct, enum, etc) */
955 prefix,
956 strlen(prefix) > 0 && strlen(name) > 0 ? " " : "",
957 /* ...this is the type name itself */
958 name,
959 /* ...suffixed by the appropriate '*', '[]' suffixes */
960 strlen(ptr_suffix) > 0 ? " " : "", ptr_suffix,
961 array_suffix, parens);
962
963 return show->state.name;
964}
965
966static const char *__btf_show_indent(struct btf_show *show)
967{
968 const char *indents = " ";
969 const char *indent = &indents[strlen(indents)];
970
971 if ((indent - show->state.depth) >= indents)
972 return indent - show->state.depth;
973 return indents;
974}
975
976static const char *btf_show_indent(struct btf_show *show)
977{
978 return show->flags & BTF_SHOW_COMPACT ? "" : __btf_show_indent(show);
979}
980
981static const char *btf_show_newline(struct btf_show *show)
982{
983 return show->flags & BTF_SHOW_COMPACT ? "" : "\n";
984}
985
986static const char *btf_show_delim(struct btf_show *show)
987{
988 if (show->state.depth == 0)
989 return "";
990
991 if ((show->flags & BTF_SHOW_COMPACT) && show->state.type &&
992 BTF_INFO_KIND(show->state.type->info) == BTF_KIND_UNION)
993 return "|";
994
995 return ",";
996}
997
998__printf(2, 3) static void btf_show(struct btf_show *show, const char *fmt, ...)
999{
1000 va_list args;
1001
1002 if (!show->state.depth_check) {
1003 va_start(args, fmt);
1004 show->showfn(show, fmt, args);
1005 va_end(args);
1006 }
1007}
1008
1009/* Macros are used here as btf_show_type_value[s]() prepends and appends
1010 * format specifiers to the format specifier passed in; these do the work of
1011 * adding indentation, delimiters etc while the caller simply has to specify
1012 * the type value(s) in the format specifier + value(s).
1013 */
1014#define btf_show_type_value(show, fmt, value) \
1015 do { \
1016 if ((value) != 0 || (show->flags & BTF_SHOW_ZERO) || \
1017 show->state.depth == 0) { \
1018 btf_show(show, "%s%s" fmt "%s%s", \
1019 btf_show_indent(show), \
1020 btf_show_name(show), \
1021 value, btf_show_delim(show), \
1022 btf_show_newline(show)); \
1023 if (show->state.depth > show->state.depth_to_show) \
1024 show->state.depth_to_show = show->state.depth; \
1025 } \
1026 } while (0)
1027
1028#define btf_show_type_values(show, fmt, ...) \
1029 do { \
1030 btf_show(show, "%s%s" fmt "%s%s", btf_show_indent(show), \
1031 btf_show_name(show), \
1032 __VA_ARGS__, btf_show_delim(show), \
1033 btf_show_newline(show)); \
1034 if (show->state.depth > show->state.depth_to_show) \
1035 show->state.depth_to_show = show->state.depth; \
1036 } while (0)
1037
1038/* How much is left to copy to safe buffer after @data? */
1039static int btf_show_obj_size_left(struct btf_show *show, void *data)
1040{
1041 return show->obj.head + show->obj.size - data;
1042}
1043
1044/* Is object pointed to by @data of @size already copied to our safe buffer? */
1045static bool btf_show_obj_is_safe(struct btf_show *show, void *data, int size)
1046{
1047 return data >= show->obj.data &&
1048 (data + size) < (show->obj.data + BTF_SHOW_OBJ_SAFE_SIZE);
1049}
1050
1051/*
1052 * If object pointed to by @data of @size falls within our safe buffer, return
1053 * the equivalent pointer to the same safe data. Assumes
1054 * copy_from_kernel_nofault() has already happened and our safe buffer is
1055 * populated.
1056 */
1057static void *__btf_show_obj_safe(struct btf_show *show, void *data, int size)
1058{
1059 if (btf_show_obj_is_safe(show, data, size))
1060 return show->obj.safe + (data - show->obj.data);
1061 return NULL;
1062}
1063
1064/*
1065 * Return a safe-to-access version of data pointed to by @data.
1066 * We do this by copying the relevant amount of information
1067 * to the struct btf_show obj.safe buffer using copy_from_kernel_nofault().
1068 *
1069 * If BTF_SHOW_UNSAFE is specified, just return data as-is; no
1070 * safe copy is needed.
1071 *
1072 * Otherwise we need to determine if we have the required amount
1073 * of data (determined by the @data pointer and the size of the
1074 * largest base type we can encounter (represented by
1075 * BTF_SHOW_OBJ_BASE_TYPE_SIZE). Having that much data ensures
1076 * that we will be able to print some of the current object,
1077 * and if more is needed a copy will be triggered.
1078 * Some objects such as structs will not fit into the buffer;
1079 * in such cases additional copies when we iterate over their
1080 * members may be needed.
1081 *
1082 * btf_show_obj_safe() is used to return a safe buffer for
1083 * btf_show_start_type(); this ensures that as we recurse into
1084 * nested types we always have safe data for the given type.
1085 * This approach is somewhat wasteful; it's possible for example
1086 * that when iterating over a large union we'll end up copying the
1087 * same data repeatedly, but the goal is safety not performance.
1088 * We use stack data as opposed to per-CPU buffers because the
1089 * iteration over a type can take some time, and preemption handling
1090 * would greatly complicate use of the safe buffer.
1091 */
1092static void *btf_show_obj_safe(struct btf_show *show,
1093 const struct btf_type *t,
1094 void *data)
1095{
1096 const struct btf_type *rt;
1097 int size_left, size;
1098 void *safe = NULL;
1099
1100 if (show->flags & BTF_SHOW_UNSAFE)
1101 return data;
1102
1103 rt = btf_resolve_size(show->btf, t, &size);
1104 if (IS_ERR(rt)) {
1105 show->state.status = PTR_ERR(rt);
1106 return NULL;
1107 }
1108
1109 /*
1110 * Is this toplevel object? If so, set total object size and
1111 * initialize pointers. Otherwise check if we still fall within
1112 * our safe object data.
1113 */
1114 if (show->state.depth == 0) {
1115 show->obj.size = size;
1116 show->obj.head = data;
1117 } else {
1118 /*
1119 * If the size of the current object is > our remaining
1120 * safe buffer we _may_ need to do a new copy. However
1121 * consider the case of a nested struct; it's size pushes
1122 * us over the safe buffer limit, but showing any individual
1123 * struct members does not. In such cases, we don't need
1124 * to initiate a fresh copy yet; however we definitely need
1125 * at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes left
1126 * in our buffer, regardless of the current object size.
1127 * The logic here is that as we resolve types we will
1128 * hit a base type at some point, and we need to be sure
1129 * the next chunk of data is safely available to display
1130 * that type info safely. We cannot rely on the size of
1131 * the current object here because it may be much larger
1132 * than our current buffer (e.g. task_struct is 8k).
1133 * All we want to do here is ensure that we can print the
1134 * next basic type, which we can if either
1135 * - the current type size is within the safe buffer; or
1136 * - at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes are left in
1137 * the safe buffer.
1138 */
1139 safe = __btf_show_obj_safe(show, data,
1140 min(size,
1141 BTF_SHOW_OBJ_BASE_TYPE_SIZE));
1142 }
1143
1144 /*
1145 * We need a new copy to our safe object, either because we haven't
1146 * yet copied and are initializing safe data, or because the data
1147 * we want falls outside the boundaries of the safe object.
1148 */
1149 if (!safe) {
1150 size_left = btf_show_obj_size_left(show, data);
1151 if (size_left > BTF_SHOW_OBJ_SAFE_SIZE)
1152 size_left = BTF_SHOW_OBJ_SAFE_SIZE;
1153 show->state.status = copy_from_kernel_nofault(show->obj.safe,
1154 data, size_left);
1155 if (!show->state.status) {
1156 show->obj.data = data;
1157 safe = show->obj.safe;
1158 }
1159 }
1160
1161 return safe;
1162}
1163
1164/*
1165 * Set the type we are starting to show and return a safe data pointer
1166 * to be used for showing the associated data.
1167 */
1168static void *btf_show_start_type(struct btf_show *show,
1169 const struct btf_type *t,
1170 u32 type_id, void *data)
1171{
1172 show->state.type = t;
1173 show->state.type_id = type_id;
1174 show->state.name[0] = '\0';
1175
1176 return btf_show_obj_safe(show, t, data);
1177}
1178
1179static void btf_show_end_type(struct btf_show *show)
1180{
1181 show->state.type = NULL;
1182 show->state.type_id = 0;
1183 show->state.name[0] = '\0';
1184}
1185
1186static void *btf_show_start_aggr_type(struct btf_show *show,
1187 const struct btf_type *t,
1188 u32 type_id, void *data)
1189{
1190 void *safe_data = btf_show_start_type(show, t, type_id, data);
1191
1192 if (!safe_data)
1193 return safe_data;
1194
1195 btf_show(show, "%s%s%s", btf_show_indent(show),
1196 btf_show_name(show),
1197 btf_show_newline(show));
1198 show->state.depth++;
1199 return safe_data;
1200}
1201
1202static void btf_show_end_aggr_type(struct btf_show *show,
1203 const char *suffix)
1204{
1205 show->state.depth--;
1206 btf_show(show, "%s%s%s%s", btf_show_indent(show), suffix,
1207 btf_show_delim(show), btf_show_newline(show));
1208 btf_show_end_type(show);
1209}
1210
1211static void btf_show_start_member(struct btf_show *show,
1212 const struct btf_member *m)
1213{
1214 show->state.member = m;
1215}
1216
1217static void btf_show_start_array_member(struct btf_show *show)
1218{
1219 show->state.array_member = 1;
1220 btf_show_start_member(show, NULL);
1221}
1222
1223static void btf_show_end_member(struct btf_show *show)
1224{
1225 show->state.member = NULL;
1226}
1227
1228static void btf_show_end_array_member(struct btf_show *show)
1229{
1230 show->state.array_member = 0;
1231 btf_show_end_member(show);
1232}
1233
1234static void *btf_show_start_array_type(struct btf_show *show,
1235 const struct btf_type *t,
1236 u32 type_id,
1237 u16 array_encoding,
1238 void *data)
1239{
1240 show->state.array_encoding = array_encoding;
1241 show->state.array_terminated = 0;
1242 return btf_show_start_aggr_type(show, t, type_id, data);
1243}
1244
1245static void btf_show_end_array_type(struct btf_show *show)
1246{
1247 show->state.array_encoding = 0;
1248 show->state.array_terminated = 0;
1249 btf_show_end_aggr_type(show, "]");
1250}
1251
1252static void *btf_show_start_struct_type(struct btf_show *show,
1253 const struct btf_type *t,
1254 u32 type_id,
1255 void *data)
1256{
1257 return btf_show_start_aggr_type(show, t, type_id, data);
1258}
1259
1260static void btf_show_end_struct_type(struct btf_show *show)
1261{
1262 btf_show_end_aggr_type(show, "}");
1263}
1264
1265__printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
1266 const char *fmt, ...)
1267{
1268 va_list args;
1269
1270 va_start(args, fmt);
1271 bpf_verifier_vlog(log, fmt, args);
1272 va_end(args);
1273}
1274
1275__printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
1276 const char *fmt, ...)
1277{
1278 struct bpf_verifier_log *log = &env->log;
1279 va_list args;
1280
1281 if (!bpf_verifier_log_needed(log))
1282 return;
1283
1284 va_start(args, fmt);
1285 bpf_verifier_vlog(log, fmt, args);
1286 va_end(args);
1287}
1288
1289__printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
1290 const struct btf_type *t,
1291 bool log_details,
1292 const char *fmt, ...)
1293{
1294 struct bpf_verifier_log *log = &env->log;
1295 u8 kind = BTF_INFO_KIND(t->info);
1296 struct btf *btf = env->btf;
1297 va_list args;
1298
1299 if (!bpf_verifier_log_needed(log))
1300 return;
1301
1302 /* btf verifier prints all types it is processing via
1303 * btf_verifier_log_type(..., fmt = NULL).
1304 * Skip those prints for in-kernel BTF verification.
1305 */
1306 if (log->level == BPF_LOG_KERNEL && !fmt)
1307 return;
1308
1309 __btf_verifier_log(log, "[%u] %s %s%s",
1310 env->log_type_id,
1311 btf_kind_str[kind],
1312 __btf_name_by_offset(btf, t->name_off),
1313 log_details ? " " : "");
1314
1315 if (log_details)
1316 btf_type_ops(t)->log_details(env, t);
1317
1318 if (fmt && *fmt) {
1319 __btf_verifier_log(log, " ");
1320 va_start(args, fmt);
1321 bpf_verifier_vlog(log, fmt, args);
1322 va_end(args);
1323 }
1324
1325 __btf_verifier_log(log, "\n");
1326}
1327
1328#define btf_verifier_log_type(env, t, ...) \
1329 __btf_verifier_log_type((env), (t), true, __VA_ARGS__)
1330#define btf_verifier_log_basic(env, t, ...) \
1331 __btf_verifier_log_type((env), (t), false, __VA_ARGS__)
1332
1333__printf(4, 5)
1334static void btf_verifier_log_member(struct btf_verifier_env *env,
1335 const struct btf_type *struct_type,
1336 const struct btf_member *member,
1337 const char *fmt, ...)
1338{
1339 struct bpf_verifier_log *log = &env->log;
1340 struct btf *btf = env->btf;
1341 va_list args;
1342
1343 if (!bpf_verifier_log_needed(log))
1344 return;
1345
1346 if (log->level == BPF_LOG_KERNEL && !fmt)
1347 return;
1348 /* The CHECK_META phase already did a btf dump.
1349 *
1350 * If member is logged again, it must hit an error in
1351 * parsing this member. It is useful to print out which
1352 * struct this member belongs to.
1353 */
1354 if (env->phase != CHECK_META)
1355 btf_verifier_log_type(env, struct_type, NULL);
1356
1357 if (btf_type_kflag(struct_type))
1358 __btf_verifier_log(log,
1359 "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
1360 __btf_name_by_offset(btf, member->name_off),
1361 member->type,
1362 BTF_MEMBER_BITFIELD_SIZE(member->offset),
1363 BTF_MEMBER_BIT_OFFSET(member->offset));
1364 else
1365 __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
1366 __btf_name_by_offset(btf, member->name_off),
1367 member->type, member->offset);
1368
1369 if (fmt && *fmt) {
1370 __btf_verifier_log(log, " ");
1371 va_start(args, fmt);
1372 bpf_verifier_vlog(log, fmt, args);
1373 va_end(args);
1374 }
1375
1376 __btf_verifier_log(log, "\n");
1377}
1378
1379__printf(4, 5)
1380static void btf_verifier_log_vsi(struct btf_verifier_env *env,
1381 const struct btf_type *datasec_type,
1382 const struct btf_var_secinfo *vsi,
1383 const char *fmt, ...)
1384{
1385 struct bpf_verifier_log *log = &env->log;
1386 va_list args;
1387
1388 if (!bpf_verifier_log_needed(log))
1389 return;
1390 if (log->level == BPF_LOG_KERNEL && !fmt)
1391 return;
1392 if (env->phase != CHECK_META)
1393 btf_verifier_log_type(env, datasec_type, NULL);
1394
1395 __btf_verifier_log(log, "\t type_id=%u offset=%u size=%u",
1396 vsi->type, vsi->offset, vsi->size);
1397 if (fmt && *fmt) {
1398 __btf_verifier_log(log, " ");
1399 va_start(args, fmt);
1400 bpf_verifier_vlog(log, fmt, args);
1401 va_end(args);
1402 }
1403
1404 __btf_verifier_log(log, "\n");
1405}
1406
1407static void btf_verifier_log_hdr(struct btf_verifier_env *env,
1408 u32 btf_data_size)
1409{
1410 struct bpf_verifier_log *log = &env->log;
1411 const struct btf *btf = env->btf;
1412 const struct btf_header *hdr;
1413
1414 if (!bpf_verifier_log_needed(log))
1415 return;
1416
1417 if (log->level == BPF_LOG_KERNEL)
1418 return;
1419 hdr = &btf->hdr;
1420 __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
1421 __btf_verifier_log(log, "version: %u\n", hdr->version);
1422 __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
1423 __btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
1424 __btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
1425 __btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
1426 __btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
1427 __btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
1428 __btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
1429}
1430
1431static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
1432{
1433 struct btf *btf = env->btf;
1434
1435 if (btf->types_size == btf->nr_types) {
1436 /* Expand 'types' array */
1437
1438 struct btf_type **new_types;
1439 u32 expand_by, new_size;
1440
1441 if (btf->start_id + btf->types_size == BTF_MAX_TYPE) {
1442 btf_verifier_log(env, "Exceeded max num of types");
1443 return -E2BIG;
1444 }
1445
1446 expand_by = max_t(u32, btf->types_size >> 2, 16);
1447 new_size = min_t(u32, BTF_MAX_TYPE,
1448 btf->types_size + expand_by);
1449
1450 new_types = kvcalloc(new_size, sizeof(*new_types),
1451 GFP_KERNEL | __GFP_NOWARN);
1452 if (!new_types)
1453 return -ENOMEM;
1454
1455 if (btf->nr_types == 0) {
1456 if (!btf->base_btf) {
1457 /* lazily init VOID type */
1458 new_types[0] = &btf_void;
1459 btf->nr_types++;
1460 }
1461 } else {
1462 memcpy(new_types, btf->types,
1463 sizeof(*btf->types) * btf->nr_types);
1464 }
1465
1466 kvfree(btf->types);
1467 btf->types = new_types;
1468 btf->types_size = new_size;
1469 }
1470
1471 btf->types[btf->nr_types++] = t;
1472
1473 return 0;
1474}
1475
1476static int btf_alloc_id(struct btf *btf)
1477{
1478 int id;
1479
1480 idr_preload(GFP_KERNEL);
1481 spin_lock_bh(&btf_idr_lock);
1482 id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
1483 if (id > 0)
1484 btf->id = id;
1485 spin_unlock_bh(&btf_idr_lock);
1486 idr_preload_end();
1487
1488 if (WARN_ON_ONCE(!id))
1489 return -ENOSPC;
1490
1491 return id > 0 ? 0 : id;
1492}
1493
1494static void btf_free_id(struct btf *btf)
1495{
1496 unsigned long flags;
1497
1498 /*
1499 * In map-in-map, calling map_delete_elem() on outer
1500 * map will call bpf_map_put on the inner map.
1501 * It will then eventually call btf_free_id()
1502 * on the inner map. Some of the map_delete_elem()
1503 * implementation may have irq disabled, so
1504 * we need to use the _irqsave() version instead
1505 * of the _bh() version.
1506 */
1507 spin_lock_irqsave(&btf_idr_lock, flags);
1508 idr_remove(&btf_idr, btf->id);
1509 spin_unlock_irqrestore(&btf_idr_lock, flags);
1510}
1511
1512static void btf_free(struct btf *btf)
1513{
1514 kvfree(btf->types);
1515 kvfree(btf->resolved_sizes);
1516 kvfree(btf->resolved_ids);
1517 kvfree(btf->data);
1518 kfree(btf);
1519}
1520
1521static void btf_free_rcu(struct rcu_head *rcu)
1522{
1523 struct btf *btf = container_of(rcu, struct btf, rcu);
1524
1525 btf_free(btf);
1526}
1527
1528void btf_get(struct btf *btf)
1529{
1530 refcount_inc(&btf->refcnt);
1531}
1532
1533void btf_put(struct btf *btf)
1534{
1535 if (btf && refcount_dec_and_test(&btf->refcnt)) {
1536 btf_free_id(btf);
1537 call_rcu(&btf->rcu, btf_free_rcu);
1538 }
1539}
1540
1541static int env_resolve_init(struct btf_verifier_env *env)
1542{
1543 struct btf *btf = env->btf;
1544 u32 nr_types = btf->nr_types;
1545 u32 *resolved_sizes = NULL;
1546 u32 *resolved_ids = NULL;
1547 u8 *visit_states = NULL;
1548
1549 resolved_sizes = kvcalloc(nr_types, sizeof(*resolved_sizes),
1550 GFP_KERNEL | __GFP_NOWARN);
1551 if (!resolved_sizes)
1552 goto nomem;
1553
1554 resolved_ids = kvcalloc(nr_types, sizeof(*resolved_ids),
1555 GFP_KERNEL | __GFP_NOWARN);
1556 if (!resolved_ids)
1557 goto nomem;
1558
1559 visit_states = kvcalloc(nr_types, sizeof(*visit_states),
1560 GFP_KERNEL | __GFP_NOWARN);
1561 if (!visit_states)
1562 goto nomem;
1563
1564 btf->resolved_sizes = resolved_sizes;
1565 btf->resolved_ids = resolved_ids;
1566 env->visit_states = visit_states;
1567
1568 return 0;
1569
1570nomem:
1571 kvfree(resolved_sizes);
1572 kvfree(resolved_ids);
1573 kvfree(visit_states);
1574 return -ENOMEM;
1575}
1576
1577static void btf_verifier_env_free(struct btf_verifier_env *env)
1578{
1579 kvfree(env->visit_states);
1580 kfree(env);
1581}
1582
1583static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
1584 const struct btf_type *next_type)
1585{
1586 switch (env->resolve_mode) {
1587 case RESOLVE_TBD:
1588 /* int, enum or void is a sink */
1589 return !btf_type_needs_resolve(next_type);
1590 case RESOLVE_PTR:
1591 /* int, enum, void, struct, array, func or func_proto is a sink
1592 * for ptr
1593 */
1594 return !btf_type_is_modifier(next_type) &&
1595 !btf_type_is_ptr(next_type);
1596 case RESOLVE_STRUCT_OR_ARRAY:
1597 /* int, enum, void, ptr, func or func_proto is a sink
1598 * for struct and array
1599 */
1600 return !btf_type_is_modifier(next_type) &&
1601 !btf_type_is_array(next_type) &&
1602 !btf_type_is_struct(next_type);
1603 default:
1604 BUG();
1605 }
1606}
1607
1608static bool env_type_is_resolved(const struct btf_verifier_env *env,
1609 u32 type_id)
1610{
1611 /* base BTF types should be resolved by now */
1612 if (type_id < env->btf->start_id)
1613 return true;
1614
1615 return env->visit_states[type_id - env->btf->start_id] == RESOLVED;
1616}
1617
1618static int env_stack_push(struct btf_verifier_env *env,
1619 const struct btf_type *t, u32 type_id)
1620{
1621 const struct btf *btf = env->btf;
1622 struct resolve_vertex *v;
1623
1624 if (env->top_stack == MAX_RESOLVE_DEPTH)
1625 return -E2BIG;
1626
1627 if (type_id < btf->start_id
1628 || env->visit_states[type_id - btf->start_id] != NOT_VISITED)
1629 return -EEXIST;
1630
1631 env->visit_states[type_id - btf->start_id] = VISITED;
1632
1633 v = &env->stack[env->top_stack++];
1634 v->t = t;
1635 v->type_id = type_id;
1636 v->next_member = 0;
1637
1638 if (env->resolve_mode == RESOLVE_TBD) {
1639 if (btf_type_is_ptr(t))
1640 env->resolve_mode = RESOLVE_PTR;
1641 else if (btf_type_is_struct(t) || btf_type_is_array(t))
1642 env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
1643 }
1644
1645 return 0;
1646}
1647
1648static void env_stack_set_next_member(struct btf_verifier_env *env,
1649 u16 next_member)
1650{
1651 env->stack[env->top_stack - 1].next_member = next_member;
1652}
1653
1654static void env_stack_pop_resolved(struct btf_verifier_env *env,
1655 u32 resolved_type_id,
1656 u32 resolved_size)
1657{
1658 u32 type_id = env->stack[--(env->top_stack)].type_id;
1659 struct btf *btf = env->btf;
1660
1661 type_id -= btf->start_id; /* adjust to local type id */
1662 btf->resolved_sizes[type_id] = resolved_size;
1663 btf->resolved_ids[type_id] = resolved_type_id;
1664 env->visit_states[type_id] = RESOLVED;
1665}
1666
1667static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
1668{
1669 return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
1670}
1671
1672/* Resolve the size of a passed-in "type"
1673 *
1674 * type: is an array (e.g. u32 array[x][y])
1675 * return type: type "u32[x][y]", i.e. BTF_KIND_ARRAY,
1676 * *type_size: (x * y * sizeof(u32)). Hence, *type_size always
1677 * corresponds to the return type.
1678 * *elem_type: u32
1679 * *elem_id: id of u32
1680 * *total_nelems: (x * y). Hence, individual elem size is
1681 * (*type_size / *total_nelems)
1682 * *type_id: id of type if it's changed within the function, 0 if not
1683 *
1684 * type: is not an array (e.g. const struct X)
1685 * return type: type "struct X"
1686 * *type_size: sizeof(struct X)
1687 * *elem_type: same as return type ("struct X")
1688 * *elem_id: 0
1689 * *total_nelems: 1
1690 * *type_id: id of type if it's changed within the function, 0 if not
1691 */
1692static const struct btf_type *
1693__btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1694 u32 *type_size, const struct btf_type **elem_type,
1695 u32 *elem_id, u32 *total_nelems, u32 *type_id)
1696{
1697 const struct btf_type *array_type = NULL;
1698 const struct btf_array *array = NULL;
1699 u32 i, size, nelems = 1, id = 0;
1700
1701 for (i = 0; i < MAX_RESOLVE_DEPTH; i++) {
1702 switch (BTF_INFO_KIND(type->info)) {
1703 /* type->size can be used */
1704 case BTF_KIND_INT:
1705 case BTF_KIND_STRUCT:
1706 case BTF_KIND_UNION:
1707 case BTF_KIND_ENUM:
1708 case BTF_KIND_FLOAT:
1709 size = type->size;
1710 goto resolved;
1711
1712 case BTF_KIND_PTR:
1713 size = sizeof(void *);
1714 goto resolved;
1715
1716 /* Modifiers */
1717 case BTF_KIND_TYPEDEF:
1718 case BTF_KIND_VOLATILE:
1719 case BTF_KIND_CONST:
1720 case BTF_KIND_RESTRICT:
1721 id = type->type;
1722 type = btf_type_by_id(btf, type->type);
1723 break;
1724
1725 case BTF_KIND_ARRAY:
1726 if (!array_type)
1727 array_type = type;
1728 array = btf_type_array(type);
1729 if (nelems && array->nelems > U32_MAX / nelems)
1730 return ERR_PTR(-EINVAL);
1731 nelems *= array->nelems;
1732 type = btf_type_by_id(btf, array->type);
1733 break;
1734
1735 /* type without size */
1736 default:
1737 return ERR_PTR(-EINVAL);
1738 }
1739 }
1740
1741 return ERR_PTR(-EINVAL);
1742
1743resolved:
1744 if (nelems && size > U32_MAX / nelems)
1745 return ERR_PTR(-EINVAL);
1746
1747 *type_size = nelems * size;
1748 if (total_nelems)
1749 *total_nelems = nelems;
1750 if (elem_type)
1751 *elem_type = type;
1752 if (elem_id)
1753 *elem_id = array ? array->type : 0;
1754 if (type_id && id)
1755 *type_id = id;
1756
1757 return array_type ? : type;
1758}
1759
1760const struct btf_type *
1761btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1762 u32 *type_size)
1763{
1764 return __btf_resolve_size(btf, type, type_size, NULL, NULL, NULL, NULL);
1765}
1766
1767static u32 btf_resolved_type_id(const struct btf *btf, u32 type_id)
1768{
1769 while (type_id < btf->start_id)
1770 btf = btf->base_btf;
1771
1772 return btf->resolved_ids[type_id - btf->start_id];
1773}
1774
1775/* The input param "type_id" must point to a needs_resolve type */
1776static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
1777 u32 *type_id)
1778{
1779 *type_id = btf_resolved_type_id(btf, *type_id);
1780 return btf_type_by_id(btf, *type_id);
1781}
1782
1783static u32 btf_resolved_type_size(const struct btf *btf, u32 type_id)
1784{
1785 while (type_id < btf->start_id)
1786 btf = btf->base_btf;
1787
1788 return btf->resolved_sizes[type_id - btf->start_id];
1789}
1790
1791const struct btf_type *btf_type_id_size(const struct btf *btf,
1792 u32 *type_id, u32 *ret_size)
1793{
1794 const struct btf_type *size_type;
1795 u32 size_type_id = *type_id;
1796 u32 size = 0;
1797
1798 size_type = btf_type_by_id(btf, size_type_id);
1799 if (btf_type_nosize_or_null(size_type))
1800 return NULL;
1801
1802 if (btf_type_has_size(size_type)) {
1803 size = size_type->size;
1804 } else if (btf_type_is_array(size_type)) {
1805 size = btf_resolved_type_size(btf, size_type_id);
1806 } else if (btf_type_is_ptr(size_type)) {
1807 size = sizeof(void *);
1808 } else {
1809 if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) &&
1810 !btf_type_is_var(size_type)))
1811 return NULL;
1812
1813 size_type_id = btf_resolved_type_id(btf, size_type_id);
1814 size_type = btf_type_by_id(btf, size_type_id);
1815 if (btf_type_nosize_or_null(size_type))
1816 return NULL;
1817 else if (btf_type_has_size(size_type))
1818 size = size_type->size;
1819 else if (btf_type_is_array(size_type))
1820 size = btf_resolved_type_size(btf, size_type_id);
1821 else if (btf_type_is_ptr(size_type))
1822 size = sizeof(void *);
1823 else
1824 return NULL;
1825 }
1826
1827 *type_id = size_type_id;
1828 if (ret_size)
1829 *ret_size = size;
1830
1831 return size_type;
1832}
1833
1834static int btf_df_check_member(struct btf_verifier_env *env,
1835 const struct btf_type *struct_type,
1836 const struct btf_member *member,
1837 const struct btf_type *member_type)
1838{
1839 btf_verifier_log_basic(env, struct_type,
1840 "Unsupported check_member");
1841 return -EINVAL;
1842}
1843
1844static int btf_df_check_kflag_member(struct btf_verifier_env *env,
1845 const struct btf_type *struct_type,
1846 const struct btf_member *member,
1847 const struct btf_type *member_type)
1848{
1849 btf_verifier_log_basic(env, struct_type,
1850 "Unsupported check_kflag_member");
1851 return -EINVAL;
1852}
1853
1854/* Used for ptr, array struct/union and float type members.
1855 * int, enum and modifier types have their specific callback functions.
1856 */
1857static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
1858 const struct btf_type *struct_type,
1859 const struct btf_member *member,
1860 const struct btf_type *member_type)
1861{
1862 if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) {
1863 btf_verifier_log_member(env, struct_type, member,
1864 "Invalid member bitfield_size");
1865 return -EINVAL;
1866 }
1867
1868 /* bitfield size is 0, so member->offset represents bit offset only.
1869 * It is safe to call non kflag check_member variants.
1870 */
1871 return btf_type_ops(member_type)->check_member(env, struct_type,
1872 member,
1873 member_type);
1874}
1875
1876static int btf_df_resolve(struct btf_verifier_env *env,
1877 const struct resolve_vertex *v)
1878{
1879 btf_verifier_log_basic(env, v->t, "Unsupported resolve");
1880 return -EINVAL;
1881}
1882
1883static void btf_df_show(const struct btf *btf, const struct btf_type *t,
1884 u32 type_id, void *data, u8 bits_offsets,
1885 struct btf_show *show)
1886{
1887 btf_show(show, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
1888}
1889
1890static int btf_int_check_member(struct btf_verifier_env *env,
1891 const struct btf_type *struct_type,
1892 const struct btf_member *member,
1893 const struct btf_type *member_type)
1894{
1895 u32 int_data = btf_type_int(member_type);
1896 u32 struct_bits_off = member->offset;
1897 u32 struct_size = struct_type->size;
1898 u32 nr_copy_bits;
1899 u32 bytes_offset;
1900
1901 if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
1902 btf_verifier_log_member(env, struct_type, member,
1903 "bits_offset exceeds U32_MAX");
1904 return -EINVAL;
1905 }
1906
1907 struct_bits_off += BTF_INT_OFFSET(int_data);
1908 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1909 nr_copy_bits = BTF_INT_BITS(int_data) +
1910 BITS_PER_BYTE_MASKED(struct_bits_off);
1911
1912 if (nr_copy_bits > BITS_PER_U128) {
1913 btf_verifier_log_member(env, struct_type, member,
1914 "nr_copy_bits exceeds 128");
1915 return -EINVAL;
1916 }
1917
1918 if (struct_size < bytes_offset ||
1919 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
1920 btf_verifier_log_member(env, struct_type, member,
1921 "Member exceeds struct_size");
1922 return -EINVAL;
1923 }
1924
1925 return 0;
1926}
1927
1928static int btf_int_check_kflag_member(struct btf_verifier_env *env,
1929 const struct btf_type *struct_type,
1930 const struct btf_member *member,
1931 const struct btf_type *member_type)
1932{
1933 u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset;
1934 u32 int_data = btf_type_int(member_type);
1935 u32 struct_size = struct_type->size;
1936 u32 nr_copy_bits;
1937
1938 /* a regular int type is required for the kflag int member */
1939 if (!btf_type_int_is_regular(member_type)) {
1940 btf_verifier_log_member(env, struct_type, member,
1941 "Invalid member base type");
1942 return -EINVAL;
1943 }
1944
1945 /* check sanity of bitfield size */
1946 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
1947 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
1948 nr_int_data_bits = BTF_INT_BITS(int_data);
1949 if (!nr_bits) {
1950 /* Not a bitfield member, member offset must be at byte
1951 * boundary.
1952 */
1953 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
1954 btf_verifier_log_member(env, struct_type, member,
1955 "Invalid member offset");
1956 return -EINVAL;
1957 }
1958
1959 nr_bits = nr_int_data_bits;
1960 } else if (nr_bits > nr_int_data_bits) {
1961 btf_verifier_log_member(env, struct_type, member,
1962 "Invalid member bitfield_size");
1963 return -EINVAL;
1964 }
1965
1966 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1967 nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off);
1968 if (nr_copy_bits > BITS_PER_U128) {
1969 btf_verifier_log_member(env, struct_type, member,
1970 "nr_copy_bits exceeds 128");
1971 return -EINVAL;
1972 }
1973
1974 if (struct_size < bytes_offset ||
1975 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
1976 btf_verifier_log_member(env, struct_type, member,
1977 "Member exceeds struct_size");
1978 return -EINVAL;
1979 }
1980
1981 return 0;
1982}
1983
1984static s32 btf_int_check_meta(struct btf_verifier_env *env,
1985 const struct btf_type *t,
1986 u32 meta_left)
1987{
1988 u32 int_data, nr_bits, meta_needed = sizeof(int_data);
1989 u16 encoding;
1990
1991 if (meta_left < meta_needed) {
1992 btf_verifier_log_basic(env, t,
1993 "meta_left:%u meta_needed:%u",
1994 meta_left, meta_needed);
1995 return -EINVAL;
1996 }
1997
1998 if (btf_type_vlen(t)) {
1999 btf_verifier_log_type(env, t, "vlen != 0");
2000 return -EINVAL;
2001 }
2002
2003 if (btf_type_kflag(t)) {
2004 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2005 return -EINVAL;
2006 }
2007
2008 int_data = btf_type_int(t);
2009 if (int_data & ~BTF_INT_MASK) {
2010 btf_verifier_log_basic(env, t, "Invalid int_data:%x",
2011 int_data);
2012 return -EINVAL;
2013 }
2014
2015 nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);
2016
2017 if (nr_bits > BITS_PER_U128) {
2018 btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
2019 BITS_PER_U128);
2020 return -EINVAL;
2021 }
2022
2023 if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
2024 btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
2025 return -EINVAL;
2026 }
2027
2028 /*
2029 * Only one of the encoding bits is allowed and it
2030 * should be sufficient for the pretty print purpose (i.e. decoding).
2031 * Multiple bits can be allowed later if it is found
2032 * to be insufficient.
2033 */
2034 encoding = BTF_INT_ENCODING(int_data);
2035 if (encoding &&
2036 encoding != BTF_INT_SIGNED &&
2037 encoding != BTF_INT_CHAR &&
2038 encoding != BTF_INT_BOOL) {
2039 btf_verifier_log_type(env, t, "Unsupported encoding");
2040 return -ENOTSUPP;
2041 }
2042
2043 btf_verifier_log_type(env, t, NULL);
2044
2045 return meta_needed;
2046}
2047
2048static void btf_int_log(struct btf_verifier_env *env,
2049 const struct btf_type *t)
2050{
2051 int int_data = btf_type_int(t);
2052
2053 btf_verifier_log(env,
2054 "size=%u bits_offset=%u nr_bits=%u encoding=%s",
2055 t->size, BTF_INT_OFFSET(int_data),
2056 BTF_INT_BITS(int_data),
2057 btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
2058}
2059
2060static void btf_int128_print(struct btf_show *show, void *data)
2061{
2062 /* data points to a __int128 number.
2063 * Suppose
2064 * int128_num = *(__int128 *)data;
2065 * The below formulas shows what upper_num and lower_num represents:
2066 * upper_num = int128_num >> 64;
2067 * lower_num = int128_num & 0xffffffffFFFFFFFFULL;
2068 */
2069 u64 upper_num, lower_num;
2070
2071#ifdef __BIG_ENDIAN_BITFIELD
2072 upper_num = *(u64 *)data;
2073 lower_num = *(u64 *)(data + 8);
2074#else
2075 upper_num = *(u64 *)(data + 8);
2076 lower_num = *(u64 *)data;
2077#endif
2078 if (upper_num == 0)
2079 btf_show_type_value(show, "0x%llx", lower_num);
2080 else
2081 btf_show_type_values(show, "0x%llx%016llx", upper_num,
2082 lower_num);
2083}
2084
2085static void btf_int128_shift(u64 *print_num, u16 left_shift_bits,
2086 u16 right_shift_bits)
2087{
2088 u64 upper_num, lower_num;
2089
2090#ifdef __BIG_ENDIAN_BITFIELD
2091 upper_num = print_num[0];
2092 lower_num = print_num[1];
2093#else
2094 upper_num = print_num[1];
2095 lower_num = print_num[0];
2096#endif
2097
2098 /* shake out un-needed bits by shift/or operations */
2099 if (left_shift_bits >= 64) {
2100 upper_num = lower_num << (left_shift_bits - 64);
2101 lower_num = 0;
2102 } else {
2103 upper_num = (upper_num << left_shift_bits) |
2104 (lower_num >> (64 - left_shift_bits));
2105 lower_num = lower_num << left_shift_bits;
2106 }
2107
2108 if (right_shift_bits >= 64) {
2109 lower_num = upper_num >> (right_shift_bits - 64);
2110 upper_num = 0;
2111 } else {
2112 lower_num = (lower_num >> right_shift_bits) |
2113 (upper_num << (64 - right_shift_bits));
2114 upper_num = upper_num >> right_shift_bits;
2115 }
2116
2117#ifdef __BIG_ENDIAN_BITFIELD
2118 print_num[0] = upper_num;
2119 print_num[1] = lower_num;
2120#else
2121 print_num[0] = lower_num;
2122 print_num[1] = upper_num;
2123#endif
2124}
2125
2126static void btf_bitfield_show(void *data, u8 bits_offset,
2127 u8 nr_bits, struct btf_show *show)
2128{
2129 u16 left_shift_bits, right_shift_bits;
2130 u8 nr_copy_bytes;
2131 u8 nr_copy_bits;
2132 u64 print_num[2] = {};
2133
2134 nr_copy_bits = nr_bits + bits_offset;
2135 nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
2136
2137 memcpy(print_num, data, nr_copy_bytes);
2138
2139#ifdef __BIG_ENDIAN_BITFIELD
2140 left_shift_bits = bits_offset;
2141#else
2142 left_shift_bits = BITS_PER_U128 - nr_copy_bits;
2143#endif
2144 right_shift_bits = BITS_PER_U128 - nr_bits;
2145
2146 btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
2147 btf_int128_print(show, print_num);
2148}
2149
2150
2151static void btf_int_bits_show(const struct btf *btf,
2152 const struct btf_type *t,
2153 void *data, u8 bits_offset,
2154 struct btf_show *show)
2155{
2156 u32 int_data = btf_type_int(t);
2157 u8 nr_bits = BTF_INT_BITS(int_data);
2158 u8 total_bits_offset;
2159
2160 /*
2161 * bits_offset is at most 7.
2162 * BTF_INT_OFFSET() cannot exceed 128 bits.
2163 */
2164 total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
2165 data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
2166 bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
2167 btf_bitfield_show(data, bits_offset, nr_bits, show);
2168}
2169
2170static void btf_int_show(const struct btf *btf, const struct btf_type *t,
2171 u32 type_id, void *data, u8 bits_offset,
2172 struct btf_show *show)
2173{
2174 u32 int_data = btf_type_int(t);
2175 u8 encoding = BTF_INT_ENCODING(int_data);
2176 bool sign = encoding & BTF_INT_SIGNED;
2177 u8 nr_bits = BTF_INT_BITS(int_data);
2178 void *safe_data;
2179
2180 safe_data = btf_show_start_type(show, t, type_id, data);
2181 if (!safe_data)
2182 return;
2183
2184 if (bits_offset || BTF_INT_OFFSET(int_data) ||
2185 BITS_PER_BYTE_MASKED(nr_bits)) {
2186 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2187 goto out;
2188 }
2189
2190 switch (nr_bits) {
2191 case 128:
2192 btf_int128_print(show, safe_data);
2193 break;
2194 case 64:
2195 if (sign)
2196 btf_show_type_value(show, "%lld", *(s64 *)safe_data);
2197 else
2198 btf_show_type_value(show, "%llu", *(u64 *)safe_data);
2199 break;
2200 case 32:
2201 if (sign)
2202 btf_show_type_value(show, "%d", *(s32 *)safe_data);
2203 else
2204 btf_show_type_value(show, "%u", *(u32 *)safe_data);
2205 break;
2206 case 16:
2207 if (sign)
2208 btf_show_type_value(show, "%d", *(s16 *)safe_data);
2209 else
2210 btf_show_type_value(show, "%u", *(u16 *)safe_data);
2211 break;
2212 case 8:
2213 if (show->state.array_encoding == BTF_INT_CHAR) {
2214 /* check for null terminator */
2215 if (show->state.array_terminated)
2216 break;
2217 if (*(char *)data == '\0') {
2218 show->state.array_terminated = 1;
2219 break;
2220 }
2221 if (isprint(*(char *)data)) {
2222 btf_show_type_value(show, "'%c'",
2223 *(char *)safe_data);
2224 break;
2225 }
2226 }
2227 if (sign)
2228 btf_show_type_value(show, "%d", *(s8 *)safe_data);
2229 else
2230 btf_show_type_value(show, "%u", *(u8 *)safe_data);
2231 break;
2232 default:
2233 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2234 break;
2235 }
2236out:
2237 btf_show_end_type(show);
2238}
2239
2240static const struct btf_kind_operations int_ops = {
2241 .check_meta = btf_int_check_meta,
2242 .resolve = btf_df_resolve,
2243 .check_member = btf_int_check_member,
2244 .check_kflag_member = btf_int_check_kflag_member,
2245 .log_details = btf_int_log,
2246 .show = btf_int_show,
2247};
2248
2249static int btf_modifier_check_member(struct btf_verifier_env *env,
2250 const struct btf_type *struct_type,
2251 const struct btf_member *member,
2252 const struct btf_type *member_type)
2253{
2254 const struct btf_type *resolved_type;
2255 u32 resolved_type_id = member->type;
2256 struct btf_member resolved_member;
2257 struct btf *btf = env->btf;
2258
2259 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2260 if (!resolved_type) {
2261 btf_verifier_log_member(env, struct_type, member,
2262 "Invalid member");
2263 return -EINVAL;
2264 }
2265
2266 resolved_member = *member;
2267 resolved_member.type = resolved_type_id;
2268
2269 return btf_type_ops(resolved_type)->check_member(env, struct_type,
2270 &resolved_member,
2271 resolved_type);
2272}
2273
2274static int btf_modifier_check_kflag_member(struct btf_verifier_env *env,
2275 const struct btf_type *struct_type,
2276 const struct btf_member *member,
2277 const struct btf_type *member_type)
2278{
2279 const struct btf_type *resolved_type;
2280 u32 resolved_type_id = member->type;
2281 struct btf_member resolved_member;
2282 struct btf *btf = env->btf;
2283
2284 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2285 if (!resolved_type) {
2286 btf_verifier_log_member(env, struct_type, member,
2287 "Invalid member");
2288 return -EINVAL;
2289 }
2290
2291 resolved_member = *member;
2292 resolved_member.type = resolved_type_id;
2293
2294 return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type,
2295 &resolved_member,
2296 resolved_type);
2297}
2298
2299static int btf_ptr_check_member(struct btf_verifier_env *env,
2300 const struct btf_type *struct_type,
2301 const struct btf_member *member,
2302 const struct btf_type *member_type)
2303{
2304 u32 struct_size, struct_bits_off, bytes_offset;
2305
2306 struct_size = struct_type->size;
2307 struct_bits_off = member->offset;
2308 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2309
2310 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2311 btf_verifier_log_member(env, struct_type, member,
2312 "Member is not byte aligned");
2313 return -EINVAL;
2314 }
2315
2316 if (struct_size - bytes_offset < sizeof(void *)) {
2317 btf_verifier_log_member(env, struct_type, member,
2318 "Member exceeds struct_size");
2319 return -EINVAL;
2320 }
2321
2322 return 0;
2323}
2324
2325static int btf_ref_type_check_meta(struct btf_verifier_env *env,
2326 const struct btf_type *t,
2327 u32 meta_left)
2328{
2329 if (btf_type_vlen(t)) {
2330 btf_verifier_log_type(env, t, "vlen != 0");
2331 return -EINVAL;
2332 }
2333
2334 if (btf_type_kflag(t)) {
2335 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2336 return -EINVAL;
2337 }
2338
2339 if (!BTF_TYPE_ID_VALID(t->type)) {
2340 btf_verifier_log_type(env, t, "Invalid type_id");
2341 return -EINVAL;
2342 }
2343
2344 /* typedef type must have a valid name, and other ref types,
2345 * volatile, const, restrict, should have a null name.
2346 */
2347 if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
2348 if (!t->name_off ||
2349 !btf_name_valid_identifier(env->btf, t->name_off)) {
2350 btf_verifier_log_type(env, t, "Invalid name");
2351 return -EINVAL;
2352 }
2353 } else {
2354 if (t->name_off) {
2355 btf_verifier_log_type(env, t, "Invalid name");
2356 return -EINVAL;
2357 }
2358 }
2359
2360 btf_verifier_log_type(env, t, NULL);
2361
2362 return 0;
2363}
2364
2365static int btf_modifier_resolve(struct btf_verifier_env *env,
2366 const struct resolve_vertex *v)
2367{
2368 const struct btf_type *t = v->t;
2369 const struct btf_type *next_type;
2370 u32 next_type_id = t->type;
2371 struct btf *btf = env->btf;
2372
2373 next_type = btf_type_by_id(btf, next_type_id);
2374 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2375 btf_verifier_log_type(env, v->t, "Invalid type_id");
2376 return -EINVAL;
2377 }
2378
2379 if (!env_type_is_resolve_sink(env, next_type) &&
2380 !env_type_is_resolved(env, next_type_id))
2381 return env_stack_push(env, next_type, next_type_id);
2382
2383 /* Figure out the resolved next_type_id with size.
2384 * They will be stored in the current modifier's
2385 * resolved_ids and resolved_sizes such that it can
2386 * save us a few type-following when we use it later (e.g. in
2387 * pretty print).
2388 */
2389 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2390 if (env_type_is_resolved(env, next_type_id))
2391 next_type = btf_type_id_resolve(btf, &next_type_id);
2392
2393 /* "typedef void new_void", "const void"...etc */
2394 if (!btf_type_is_void(next_type) &&
2395 !btf_type_is_fwd(next_type) &&
2396 !btf_type_is_func_proto(next_type)) {
2397 btf_verifier_log_type(env, v->t, "Invalid type_id");
2398 return -EINVAL;
2399 }
2400 }
2401
2402 env_stack_pop_resolved(env, next_type_id, 0);
2403
2404 return 0;
2405}
2406
2407static int btf_var_resolve(struct btf_verifier_env *env,
2408 const struct resolve_vertex *v)
2409{
2410 const struct btf_type *next_type;
2411 const struct btf_type *t = v->t;
2412 u32 next_type_id = t->type;
2413 struct btf *btf = env->btf;
2414
2415 next_type = btf_type_by_id(btf, next_type_id);
2416 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2417 btf_verifier_log_type(env, v->t, "Invalid type_id");
2418 return -EINVAL;
2419 }
2420
2421 if (!env_type_is_resolve_sink(env, next_type) &&
2422 !env_type_is_resolved(env, next_type_id))
2423 return env_stack_push(env, next_type, next_type_id);
2424
2425 if (btf_type_is_modifier(next_type)) {
2426 const struct btf_type *resolved_type;
2427 u32 resolved_type_id;
2428
2429 resolved_type_id = next_type_id;
2430 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2431
2432 if (btf_type_is_ptr(resolved_type) &&
2433 !env_type_is_resolve_sink(env, resolved_type) &&
2434 !env_type_is_resolved(env, resolved_type_id))
2435 return env_stack_push(env, resolved_type,
2436 resolved_type_id);
2437 }
2438
2439 /* We must resolve to something concrete at this point, no
2440 * forward types or similar that would resolve to size of
2441 * zero is allowed.
2442 */
2443 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2444 btf_verifier_log_type(env, v->t, "Invalid type_id");
2445 return -EINVAL;
2446 }
2447
2448 env_stack_pop_resolved(env, next_type_id, 0);
2449
2450 return 0;
2451}
2452
2453static int btf_ptr_resolve(struct btf_verifier_env *env,
2454 const struct resolve_vertex *v)
2455{
2456 const struct btf_type *next_type;
2457 const struct btf_type *t = v->t;
2458 u32 next_type_id = t->type;
2459 struct btf *btf = env->btf;
2460
2461 next_type = btf_type_by_id(btf, next_type_id);
2462 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2463 btf_verifier_log_type(env, v->t, "Invalid type_id");
2464 return -EINVAL;
2465 }
2466
2467 if (!env_type_is_resolve_sink(env, next_type) &&
2468 !env_type_is_resolved(env, next_type_id))
2469 return env_stack_push(env, next_type, next_type_id);
2470
2471 /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
2472 * the modifier may have stopped resolving when it was resolved
2473 * to a ptr (last-resolved-ptr).
2474 *
2475 * We now need to continue from the last-resolved-ptr to
2476 * ensure the last-resolved-ptr will not referring back to
2477 * the currenct ptr (t).
2478 */
2479 if (btf_type_is_modifier(next_type)) {
2480 const struct btf_type *resolved_type;
2481 u32 resolved_type_id;
2482
2483 resolved_type_id = next_type_id;
2484 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2485
2486 if (btf_type_is_ptr(resolved_type) &&
2487 !env_type_is_resolve_sink(env, resolved_type) &&
2488 !env_type_is_resolved(env, resolved_type_id))
2489 return env_stack_push(env, resolved_type,
2490 resolved_type_id);
2491 }
2492
2493 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2494 if (env_type_is_resolved(env, next_type_id))
2495 next_type = btf_type_id_resolve(btf, &next_type_id);
2496
2497 if (!btf_type_is_void(next_type) &&
2498 !btf_type_is_fwd(next_type) &&
2499 !btf_type_is_func_proto(next_type)) {
2500 btf_verifier_log_type(env, v->t, "Invalid type_id");
2501 return -EINVAL;
2502 }
2503 }
2504
2505 env_stack_pop_resolved(env, next_type_id, 0);
2506
2507 return 0;
2508}
2509
2510static void btf_modifier_show(const struct btf *btf,
2511 const struct btf_type *t,
2512 u32 type_id, void *data,
2513 u8 bits_offset, struct btf_show *show)
2514{
2515 if (btf->resolved_ids)
2516 t = btf_type_id_resolve(btf, &type_id);
2517 else
2518 t = btf_type_skip_modifiers(btf, type_id, NULL);
2519
2520 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2521}
2522
2523static void btf_var_show(const struct btf *btf, const struct btf_type *t,
2524 u32 type_id, void *data, u8 bits_offset,
2525 struct btf_show *show)
2526{
2527 t = btf_type_id_resolve(btf, &type_id);
2528
2529 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2530}
2531
2532static void btf_ptr_show(const struct btf *btf, const struct btf_type *t,
2533 u32 type_id, void *data, u8 bits_offset,
2534 struct btf_show *show)
2535{
2536 void *safe_data;
2537
2538 safe_data = btf_show_start_type(show, t, type_id, data);
2539 if (!safe_data)
2540 return;
2541
2542 /* It is a hashed value unless BTF_SHOW_PTR_RAW is specified */
2543 if (show->flags & BTF_SHOW_PTR_RAW)
2544 btf_show_type_value(show, "0x%px", *(void **)safe_data);
2545 else
2546 btf_show_type_value(show, "0x%p", *(void **)safe_data);
2547 btf_show_end_type(show);
2548}
2549
2550static void btf_ref_type_log(struct btf_verifier_env *env,
2551 const struct btf_type *t)
2552{
2553 btf_verifier_log(env, "type_id=%u", t->type);
2554}
2555
2556static struct btf_kind_operations modifier_ops = {
2557 .check_meta = btf_ref_type_check_meta,
2558 .resolve = btf_modifier_resolve,
2559 .check_member = btf_modifier_check_member,
2560 .check_kflag_member = btf_modifier_check_kflag_member,
2561 .log_details = btf_ref_type_log,
2562 .show = btf_modifier_show,
2563};
2564
2565static struct btf_kind_operations ptr_ops = {
2566 .check_meta = btf_ref_type_check_meta,
2567 .resolve = btf_ptr_resolve,
2568 .check_member = btf_ptr_check_member,
2569 .check_kflag_member = btf_generic_check_kflag_member,
2570 .log_details = btf_ref_type_log,
2571 .show = btf_ptr_show,
2572};
2573
2574static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
2575 const struct btf_type *t,
2576 u32 meta_left)
2577{
2578 if (btf_type_vlen(t)) {
2579 btf_verifier_log_type(env, t, "vlen != 0");
2580 return -EINVAL;
2581 }
2582
2583 if (t->type) {
2584 btf_verifier_log_type(env, t, "type != 0");
2585 return -EINVAL;
2586 }
2587
2588 /* fwd type must have a valid name */
2589 if (!t->name_off ||
2590 !btf_name_valid_identifier(env->btf, t->name_off)) {
2591 btf_verifier_log_type(env, t, "Invalid name");
2592 return -EINVAL;
2593 }
2594
2595 btf_verifier_log_type(env, t, NULL);
2596
2597 return 0;
2598}
2599
2600static void btf_fwd_type_log(struct btf_verifier_env *env,
2601 const struct btf_type *t)
2602{
2603 btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct");
2604}
2605
2606static struct btf_kind_operations fwd_ops = {
2607 .check_meta = btf_fwd_check_meta,
2608 .resolve = btf_df_resolve,
2609 .check_member = btf_df_check_member,
2610 .check_kflag_member = btf_df_check_kflag_member,
2611 .log_details = btf_fwd_type_log,
2612 .show = btf_df_show,
2613};
2614
2615static int btf_array_check_member(struct btf_verifier_env *env,
2616 const struct btf_type *struct_type,
2617 const struct btf_member *member,
2618 const struct btf_type *member_type)
2619{
2620 u32 struct_bits_off = member->offset;
2621 u32 struct_size, bytes_offset;
2622 u32 array_type_id, array_size;
2623 struct btf *btf = env->btf;
2624
2625 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2626 btf_verifier_log_member(env, struct_type, member,
2627 "Member is not byte aligned");
2628 return -EINVAL;
2629 }
2630
2631 array_type_id = member->type;
2632 btf_type_id_size(btf, &array_type_id, &array_size);
2633 struct_size = struct_type->size;
2634 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2635 if (struct_size - bytes_offset < array_size) {
2636 btf_verifier_log_member(env, struct_type, member,
2637 "Member exceeds struct_size");
2638 return -EINVAL;
2639 }
2640
2641 return 0;
2642}
2643
2644static s32 btf_array_check_meta(struct btf_verifier_env *env,
2645 const struct btf_type *t,
2646 u32 meta_left)
2647{
2648 const struct btf_array *array = btf_type_array(t);
2649 u32 meta_needed = sizeof(*array);
2650
2651 if (meta_left < meta_needed) {
2652 btf_verifier_log_basic(env, t,
2653 "meta_left:%u meta_needed:%u",
2654 meta_left, meta_needed);
2655 return -EINVAL;
2656 }
2657
2658 /* array type should not have a name */
2659 if (t->name_off) {
2660 btf_verifier_log_type(env, t, "Invalid name");
2661 return -EINVAL;
2662 }
2663
2664 if (btf_type_vlen(t)) {
2665 btf_verifier_log_type(env, t, "vlen != 0");
2666 return -EINVAL;
2667 }
2668
2669 if (btf_type_kflag(t)) {
2670 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2671 return -EINVAL;
2672 }
2673
2674 if (t->size) {
2675 btf_verifier_log_type(env, t, "size != 0");
2676 return -EINVAL;
2677 }
2678
2679 /* Array elem type and index type cannot be in type void,
2680 * so !array->type and !array->index_type are not allowed.
2681 */
2682 if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
2683 btf_verifier_log_type(env, t, "Invalid elem");
2684 return -EINVAL;
2685 }
2686
2687 if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
2688 btf_verifier_log_type(env, t, "Invalid index");
2689 return -EINVAL;
2690 }
2691
2692 btf_verifier_log_type(env, t, NULL);
2693
2694 return meta_needed;
2695}
2696
2697static int btf_array_resolve(struct btf_verifier_env *env,
2698 const struct resolve_vertex *v)
2699{
2700 const struct btf_array *array = btf_type_array(v->t);
2701 const struct btf_type *elem_type, *index_type;
2702 u32 elem_type_id, index_type_id;
2703 struct btf *btf = env->btf;
2704 u32 elem_size;
2705
2706 /* Check array->index_type */
2707 index_type_id = array->index_type;
2708 index_type = btf_type_by_id(btf, index_type_id);
2709 if (btf_type_nosize_or_null(index_type) ||
2710 btf_type_is_resolve_source_only(index_type)) {
2711 btf_verifier_log_type(env, v->t, "Invalid index");
2712 return -EINVAL;
2713 }
2714
2715 if (!env_type_is_resolve_sink(env, index_type) &&
2716 !env_type_is_resolved(env, index_type_id))
2717 return env_stack_push(env, index_type, index_type_id);
2718
2719 index_type = btf_type_id_size(btf, &index_type_id, NULL);
2720 if (!index_type || !btf_type_is_int(index_type) ||
2721 !btf_type_int_is_regular(index_type)) {
2722 btf_verifier_log_type(env, v->t, "Invalid index");
2723 return -EINVAL;
2724 }
2725
2726 /* Check array->type */
2727 elem_type_id = array->type;
2728 elem_type = btf_type_by_id(btf, elem_type_id);
2729 if (btf_type_nosize_or_null(elem_type) ||
2730 btf_type_is_resolve_source_only(elem_type)) {
2731 btf_verifier_log_type(env, v->t,
2732 "Invalid elem");
2733 return -EINVAL;
2734 }
2735
2736 if (!env_type_is_resolve_sink(env, elem_type) &&
2737 !env_type_is_resolved(env, elem_type_id))
2738 return env_stack_push(env, elem_type, elem_type_id);
2739
2740 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
2741 if (!elem_type) {
2742 btf_verifier_log_type(env, v->t, "Invalid elem");
2743 return -EINVAL;
2744 }
2745
2746 if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
2747 btf_verifier_log_type(env, v->t, "Invalid array of int");
2748 return -EINVAL;
2749 }
2750
2751 if (array->nelems && elem_size > U32_MAX / array->nelems) {
2752 btf_verifier_log_type(env, v->t,
2753 "Array size overflows U32_MAX");
2754 return -EINVAL;
2755 }
2756
2757 env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);
2758
2759 return 0;
2760}
2761
2762static void btf_array_log(struct btf_verifier_env *env,
2763 const struct btf_type *t)
2764{
2765 const struct btf_array *array = btf_type_array(t);
2766
2767 btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
2768 array->type, array->index_type, array->nelems);
2769}
2770
2771static void __btf_array_show(const struct btf *btf, const struct btf_type *t,
2772 u32 type_id, void *data, u8 bits_offset,
2773 struct btf_show *show)
2774{
2775 const struct btf_array *array = btf_type_array(t);
2776 const struct btf_kind_operations *elem_ops;
2777 const struct btf_type *elem_type;
2778 u32 i, elem_size = 0, elem_type_id;
2779 u16 encoding = 0;
2780
2781 elem_type_id = array->type;
2782 elem_type = btf_type_skip_modifiers(btf, elem_type_id, NULL);
2783 if (elem_type && btf_type_has_size(elem_type))
2784 elem_size = elem_type->size;
2785
2786 if (elem_type && btf_type_is_int(elem_type)) {
2787 u32 int_type = btf_type_int(elem_type);
2788
2789 encoding = BTF_INT_ENCODING(int_type);
2790
2791 /*
2792 * BTF_INT_CHAR encoding never seems to be set for
2793 * char arrays, so if size is 1 and element is
2794 * printable as a char, we'll do that.
2795 */
2796 if (elem_size == 1)
2797 encoding = BTF_INT_CHAR;
2798 }
2799
2800 if (!btf_show_start_array_type(show, t, type_id, encoding, data))
2801 return;
2802
2803 if (!elem_type)
2804 goto out;
2805 elem_ops = btf_type_ops(elem_type);
2806
2807 for (i = 0; i < array->nelems; i++) {
2808
2809 btf_show_start_array_member(show);
2810
2811 elem_ops->show(btf, elem_type, elem_type_id, data,
2812 bits_offset, show);
2813 data += elem_size;
2814
2815 btf_show_end_array_member(show);
2816
2817 if (show->state.array_terminated)
2818 break;
2819 }
2820out:
2821 btf_show_end_array_type(show);
2822}
2823
2824static void btf_array_show(const struct btf *btf, const struct btf_type *t,
2825 u32 type_id, void *data, u8 bits_offset,
2826 struct btf_show *show)
2827{
2828 const struct btf_member *m = show->state.member;
2829
2830 /*
2831 * First check if any members would be shown (are non-zero).
2832 * See comments above "struct btf_show" definition for more
2833 * details on how this works at a high-level.
2834 */
2835 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
2836 if (!show->state.depth_check) {
2837 show->state.depth_check = show->state.depth + 1;
2838 show->state.depth_to_show = 0;
2839 }
2840 __btf_array_show(btf, t, type_id, data, bits_offset, show);
2841 show->state.member = m;
2842
2843 if (show->state.depth_check != show->state.depth + 1)
2844 return;
2845 show->state.depth_check = 0;
2846
2847 if (show->state.depth_to_show <= show->state.depth)
2848 return;
2849 /*
2850 * Reaching here indicates we have recursed and found
2851 * non-zero array member(s).
2852 */
2853 }
2854 __btf_array_show(btf, t, type_id, data, bits_offset, show);
2855}
2856
2857static struct btf_kind_operations array_ops = {
2858 .check_meta = btf_array_check_meta,
2859 .resolve = btf_array_resolve,
2860 .check_member = btf_array_check_member,
2861 .check_kflag_member = btf_generic_check_kflag_member,
2862 .log_details = btf_array_log,
2863 .show = btf_array_show,
2864};
2865
2866static int btf_struct_check_member(struct btf_verifier_env *env,
2867 const struct btf_type *struct_type,
2868 const struct btf_member *member,
2869 const struct btf_type *member_type)
2870{
2871 u32 struct_bits_off = member->offset;
2872 u32 struct_size, bytes_offset;
2873
2874 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2875 btf_verifier_log_member(env, struct_type, member,
2876 "Member is not byte aligned");
2877 return -EINVAL;
2878 }
2879
2880 struct_size = struct_type->size;
2881 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2882 if (struct_size - bytes_offset < member_type->size) {
2883 btf_verifier_log_member(env, struct_type, member,
2884 "Member exceeds struct_size");
2885 return -EINVAL;
2886 }
2887
2888 return 0;
2889}
2890
2891static s32 btf_struct_check_meta(struct btf_verifier_env *env,
2892 const struct btf_type *t,
2893 u32 meta_left)
2894{
2895 bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
2896 const struct btf_member *member;
2897 u32 meta_needed, last_offset;
2898 struct btf *btf = env->btf;
2899 u32 struct_size = t->size;
2900 u32 offset;
2901 u16 i;
2902
2903 meta_needed = btf_type_vlen(t) * sizeof(*member);
2904 if (meta_left < meta_needed) {
2905 btf_verifier_log_basic(env, t,
2906 "meta_left:%u meta_needed:%u",
2907 meta_left, meta_needed);
2908 return -EINVAL;
2909 }
2910
2911 /* struct type either no name or a valid one */
2912 if (t->name_off &&
2913 !btf_name_valid_identifier(env->btf, t->name_off)) {
2914 btf_verifier_log_type(env, t, "Invalid name");
2915 return -EINVAL;
2916 }
2917
2918 btf_verifier_log_type(env, t, NULL);
2919
2920 last_offset = 0;
2921 for_each_member(i, t, member) {
2922 if (!btf_name_offset_valid(btf, member->name_off)) {
2923 btf_verifier_log_member(env, t, member,
2924 "Invalid member name_offset:%u",
2925 member->name_off);
2926 return -EINVAL;
2927 }
2928
2929 /* struct member either no name or a valid one */
2930 if (member->name_off &&
2931 !btf_name_valid_identifier(btf, member->name_off)) {
2932 btf_verifier_log_member(env, t, member, "Invalid name");
2933 return -EINVAL;
2934 }
2935 /* A member cannot be in type void */
2936 if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
2937 btf_verifier_log_member(env, t, member,
2938 "Invalid type_id");
2939 return -EINVAL;
2940 }
2941
2942 offset = btf_member_bit_offset(t, member);
2943 if (is_union && offset) {
2944 btf_verifier_log_member(env, t, member,
2945 "Invalid member bits_offset");
2946 return -EINVAL;
2947 }
2948
2949 /*
2950 * ">" instead of ">=" because the last member could be
2951 * "char a[0];"
2952 */
2953 if (last_offset > offset) {
2954 btf_verifier_log_member(env, t, member,
2955 "Invalid member bits_offset");
2956 return -EINVAL;
2957 }
2958
2959 if (BITS_ROUNDUP_BYTES(offset) > struct_size) {
2960 btf_verifier_log_member(env, t, member,
2961 "Member bits_offset exceeds its struct size");
2962 return -EINVAL;
2963 }
2964
2965 btf_verifier_log_member(env, t, member, NULL);
2966 last_offset = offset;
2967 }
2968
2969 return meta_needed;
2970}
2971
2972static int btf_struct_resolve(struct btf_verifier_env *env,
2973 const struct resolve_vertex *v)
2974{
2975 const struct btf_member *member;
2976 int err;
2977 u16 i;
2978
2979 /* Before continue resolving the next_member,
2980 * ensure the last member is indeed resolved to a
2981 * type with size info.
2982 */
2983 if (v->next_member) {
2984 const struct btf_type *last_member_type;
2985 const struct btf_member *last_member;
2986 u16 last_member_type_id;
2987
2988 last_member = btf_type_member(v->t) + v->next_member - 1;
2989 last_member_type_id = last_member->type;
2990 if (WARN_ON_ONCE(!env_type_is_resolved(env,
2991 last_member_type_id)))
2992 return -EINVAL;
2993
2994 last_member_type = btf_type_by_id(env->btf,
2995 last_member_type_id);
2996 if (btf_type_kflag(v->t))
2997 err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t,
2998 last_member,
2999 last_member_type);
3000 else
3001 err = btf_type_ops(last_member_type)->check_member(env, v->t,
3002 last_member,
3003 last_member_type);
3004 if (err)
3005 return err;
3006 }
3007
3008 for_each_member_from(i, v->next_member, v->t, member) {
3009 u32 member_type_id = member->type;
3010 const struct btf_type *member_type = btf_type_by_id(env->btf,
3011 member_type_id);
3012
3013 if (btf_type_nosize_or_null(member_type) ||
3014 btf_type_is_resolve_source_only(member_type)) {
3015 btf_verifier_log_member(env, v->t, member,
3016 "Invalid member");
3017 return -EINVAL;
3018 }
3019
3020 if (!env_type_is_resolve_sink(env, member_type) &&
3021 !env_type_is_resolved(env, member_type_id)) {
3022 env_stack_set_next_member(env, i + 1);
3023 return env_stack_push(env, member_type, member_type_id);
3024 }
3025
3026 if (btf_type_kflag(v->t))
3027 err = btf_type_ops(member_type)->check_kflag_member(env, v->t,
3028 member,
3029 member_type);
3030 else
3031 err = btf_type_ops(member_type)->check_member(env, v->t,
3032 member,
3033 member_type);
3034 if (err)
3035 return err;
3036 }
3037
3038 env_stack_pop_resolved(env, 0, 0);
3039
3040 return 0;
3041}
3042
3043static void btf_struct_log(struct btf_verifier_env *env,
3044 const struct btf_type *t)
3045{
3046 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3047}
3048
3049/* find 'struct bpf_spin_lock' in map value.
3050 * return >= 0 offset if found
3051 * and < 0 in case of error
3052 */
3053int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t)
3054{
3055 const struct btf_member *member;
3056 u32 i, off = -ENOENT;
3057
3058 if (!__btf_type_is_struct(t))
3059 return -EINVAL;
3060
3061 for_each_member(i, t, member) {
3062 const struct btf_type *member_type = btf_type_by_id(btf,
3063 member->type);
3064 if (!__btf_type_is_struct(member_type))
3065 continue;
3066 if (member_type->size != sizeof(struct bpf_spin_lock))
3067 continue;
3068 if (strcmp(__btf_name_by_offset(btf, member_type->name_off),
3069 "bpf_spin_lock"))
3070 continue;
3071 if (off != -ENOENT)
3072 /* only one 'struct bpf_spin_lock' is allowed */
3073 return -E2BIG;
3074 off = btf_member_bit_offset(t, member);
3075 if (off % 8)
3076 /* valid C code cannot generate such BTF */
3077 return -EINVAL;
3078 off /= 8;
3079 if (off % __alignof__(struct bpf_spin_lock))
3080 /* valid struct bpf_spin_lock will be 4 byte aligned */
3081 return -EINVAL;
3082 }
3083 return off;
3084}
3085
3086static void __btf_struct_show(const struct btf *btf, const struct btf_type *t,
3087 u32 type_id, void *data, u8 bits_offset,
3088 struct btf_show *show)
3089{
3090 const struct btf_member *member;
3091 void *safe_data;
3092 u32 i;
3093
3094 safe_data = btf_show_start_struct_type(show, t, type_id, data);
3095 if (!safe_data)
3096 return;
3097
3098 for_each_member(i, t, member) {
3099 const struct btf_type *member_type = btf_type_by_id(btf,
3100 member->type);
3101 const struct btf_kind_operations *ops;
3102 u32 member_offset, bitfield_size;
3103 u32 bytes_offset;
3104 u8 bits8_offset;
3105
3106 btf_show_start_member(show, member);
3107
3108 member_offset = btf_member_bit_offset(t, member);
3109 bitfield_size = btf_member_bitfield_size(t, member);
3110 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
3111 bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
3112 if (bitfield_size) {
3113 safe_data = btf_show_start_type(show, member_type,
3114 member->type,
3115 data + bytes_offset);
3116 if (safe_data)
3117 btf_bitfield_show(safe_data,
3118 bits8_offset,
3119 bitfield_size, show);
3120 btf_show_end_type(show);
3121 } else {
3122 ops = btf_type_ops(member_type);
3123 ops->show(btf, member_type, member->type,
3124 data + bytes_offset, bits8_offset, show);
3125 }
3126
3127 btf_show_end_member(show);
3128 }
3129
3130 btf_show_end_struct_type(show);
3131}
3132
3133static void btf_struct_show(const struct btf *btf, const struct btf_type *t,
3134 u32 type_id, void *data, u8 bits_offset,
3135 struct btf_show *show)
3136{
3137 const struct btf_member *m = show->state.member;
3138
3139 /*
3140 * First check if any members would be shown (are non-zero).
3141 * See comments above "struct btf_show" definition for more
3142 * details on how this works at a high-level.
3143 */
3144 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
3145 if (!show->state.depth_check) {
3146 show->state.depth_check = show->state.depth + 1;
3147 show->state.depth_to_show = 0;
3148 }
3149 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
3150 /* Restore saved member data here */
3151 show->state.member = m;
3152 if (show->state.depth_check != show->state.depth + 1)
3153 return;
3154 show->state.depth_check = 0;
3155
3156 if (show->state.depth_to_show <= show->state.depth)
3157 return;
3158 /*
3159 * Reaching here indicates we have recursed and found
3160 * non-zero child values.
3161 */
3162 }
3163
3164 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
3165}
3166
3167static struct btf_kind_operations struct_ops = {
3168 .check_meta = btf_struct_check_meta,
3169 .resolve = btf_struct_resolve,
3170 .check_member = btf_struct_check_member,
3171 .check_kflag_member = btf_generic_check_kflag_member,
3172 .log_details = btf_struct_log,
3173 .show = btf_struct_show,
3174};
3175
3176static int btf_enum_check_member(struct btf_verifier_env *env,
3177 const struct btf_type *struct_type,
3178 const struct btf_member *member,
3179 const struct btf_type *member_type)
3180{
3181 u32 struct_bits_off = member->offset;
3182 u32 struct_size, bytes_offset;
3183
3184 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3185 btf_verifier_log_member(env, struct_type, member,
3186 "Member is not byte aligned");
3187 return -EINVAL;
3188 }
3189
3190 struct_size = struct_type->size;
3191 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
3192 if (struct_size - bytes_offset < member_type->size) {
3193 btf_verifier_log_member(env, struct_type, member,
3194 "Member exceeds struct_size");
3195 return -EINVAL;
3196 }
3197
3198 return 0;
3199}
3200
3201static int btf_enum_check_kflag_member(struct btf_verifier_env *env,
3202 const struct btf_type *struct_type,
3203 const struct btf_member *member,
3204 const struct btf_type *member_type)
3205{
3206 u32 struct_bits_off, nr_bits, bytes_end, struct_size;
3207 u32 int_bitsize = sizeof(int) * BITS_PER_BYTE;
3208
3209 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
3210 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
3211 if (!nr_bits) {
3212 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3213 btf_verifier_log_member(env, struct_type, member,
3214 "Member is not byte aligned");
3215 return -EINVAL;
3216 }
3217
3218 nr_bits = int_bitsize;
3219 } else if (nr_bits > int_bitsize) {
3220 btf_verifier_log_member(env, struct_type, member,
3221 "Invalid member bitfield_size");
3222 return -EINVAL;
3223 }
3224
3225 struct_size = struct_type->size;
3226 bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits);
3227 if (struct_size < bytes_end) {
3228 btf_verifier_log_member(env, struct_type, member,
3229 "Member exceeds struct_size");
3230 return -EINVAL;
3231 }
3232
3233 return 0;
3234}
3235
3236static s32 btf_enum_check_meta(struct btf_verifier_env *env,
3237 const struct btf_type *t,
3238 u32 meta_left)
3239{
3240 const struct btf_enum *enums = btf_type_enum(t);
3241 struct btf *btf = env->btf;
3242 u16 i, nr_enums;
3243 u32 meta_needed;
3244
3245 nr_enums = btf_type_vlen(t);
3246 meta_needed = nr_enums * sizeof(*enums);
3247
3248 if (meta_left < meta_needed) {
3249 btf_verifier_log_basic(env, t,
3250 "meta_left:%u meta_needed:%u",
3251 meta_left, meta_needed);
3252 return -EINVAL;
3253 }
3254
3255 if (btf_type_kflag(t)) {
3256 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3257 return -EINVAL;
3258 }
3259
3260 if (t->size > 8 || !is_power_of_2(t->size)) {
3261 btf_verifier_log_type(env, t, "Unexpected size");
3262 return -EINVAL;
3263 }
3264
3265 /* enum type either no name or a valid one */
3266 if (t->name_off &&
3267 !btf_name_valid_identifier(env->btf, t->name_off)) {
3268 btf_verifier_log_type(env, t, "Invalid name");
3269 return -EINVAL;
3270 }
3271
3272 btf_verifier_log_type(env, t, NULL);
3273
3274 for (i = 0; i < nr_enums; i++) {
3275 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
3276 btf_verifier_log(env, "\tInvalid name_offset:%u",
3277 enums[i].name_off);
3278 return -EINVAL;
3279 }
3280
3281 /* enum member must have a valid name */
3282 if (!enums[i].name_off ||
3283 !btf_name_valid_identifier(btf, enums[i].name_off)) {
3284 btf_verifier_log_type(env, t, "Invalid name");
3285 return -EINVAL;
3286 }
3287
3288 if (env->log.level == BPF_LOG_KERNEL)
3289 continue;
3290 btf_verifier_log(env, "\t%s val=%d\n",
3291 __btf_name_by_offset(btf, enums[i].name_off),
3292 enums[i].val);
3293 }
3294
3295 return meta_needed;
3296}
3297
3298static void btf_enum_log(struct btf_verifier_env *env,
3299 const struct btf_type *t)
3300{
3301 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3302}
3303
3304static void btf_enum_show(const struct btf *btf, const struct btf_type *t,
3305 u32 type_id, void *data, u8 bits_offset,
3306 struct btf_show *show)
3307{
3308 const struct btf_enum *enums = btf_type_enum(t);
3309 u32 i, nr_enums = btf_type_vlen(t);
3310 void *safe_data;
3311 int v;
3312
3313 safe_data = btf_show_start_type(show, t, type_id, data);
3314 if (!safe_data)
3315 return;
3316
3317 v = *(int *)safe_data;
3318
3319 for (i = 0; i < nr_enums; i++) {
3320 if (v != enums[i].val)
3321 continue;
3322
3323 btf_show_type_value(show, "%s",
3324 __btf_name_by_offset(btf,
3325 enums[i].name_off));
3326
3327 btf_show_end_type(show);
3328 return;
3329 }
3330
3331 btf_show_type_value(show, "%d", v);
3332 btf_show_end_type(show);
3333}
3334
3335static struct btf_kind_operations enum_ops = {
3336 .check_meta = btf_enum_check_meta,
3337 .resolve = btf_df_resolve,
3338 .check_member = btf_enum_check_member,
3339 .check_kflag_member = btf_enum_check_kflag_member,
3340 .log_details = btf_enum_log,
3341 .show = btf_enum_show,
3342};
3343
3344static s32 btf_func_proto_check_meta(struct btf_verifier_env *env,
3345 const struct btf_type *t,
3346 u32 meta_left)
3347{
3348 u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param);
3349
3350 if (meta_left < meta_needed) {
3351 btf_verifier_log_basic(env, t,
3352 "meta_left:%u meta_needed:%u",
3353 meta_left, meta_needed);
3354 return -EINVAL;
3355 }
3356
3357 if (t->name_off) {
3358 btf_verifier_log_type(env, t, "Invalid name");
3359 return -EINVAL;
3360 }
3361
3362 if (btf_type_kflag(t)) {
3363 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3364 return -EINVAL;
3365 }
3366
3367 btf_verifier_log_type(env, t, NULL);
3368
3369 return meta_needed;
3370}
3371
3372static void btf_func_proto_log(struct btf_verifier_env *env,
3373 const struct btf_type *t)
3374{
3375 const struct btf_param *args = (const struct btf_param *)(t + 1);
3376 u16 nr_args = btf_type_vlen(t), i;
3377
3378 btf_verifier_log(env, "return=%u args=(", t->type);
3379 if (!nr_args) {
3380 btf_verifier_log(env, "void");
3381 goto done;
3382 }
3383
3384 if (nr_args == 1 && !args[0].type) {
3385 /* Only one vararg */
3386 btf_verifier_log(env, "vararg");
3387 goto done;
3388 }
3389
3390 btf_verifier_log(env, "%u %s", args[0].type,
3391 __btf_name_by_offset(env->btf,
3392 args[0].name_off));
3393 for (i = 1; i < nr_args - 1; i++)
3394 btf_verifier_log(env, ", %u %s", args[i].type,
3395 __btf_name_by_offset(env->btf,
3396 args[i].name_off));
3397
3398 if (nr_args > 1) {
3399 const struct btf_param *last_arg = &args[nr_args - 1];
3400
3401 if (last_arg->type)
3402 btf_verifier_log(env, ", %u %s", last_arg->type,
3403 __btf_name_by_offset(env->btf,
3404 last_arg->name_off));
3405 else
3406 btf_verifier_log(env, ", vararg");
3407 }
3408
3409done:
3410 btf_verifier_log(env, ")");
3411}
3412
3413static struct btf_kind_operations func_proto_ops = {
3414 .check_meta = btf_func_proto_check_meta,
3415 .resolve = btf_df_resolve,
3416 /*
3417 * BTF_KIND_FUNC_PROTO cannot be directly referred by
3418 * a struct's member.
3419 *
3420 * It should be a function pointer instead.
3421 * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO)
3422 *
3423 * Hence, there is no btf_func_check_member().
3424 */
3425 .check_member = btf_df_check_member,
3426 .check_kflag_member = btf_df_check_kflag_member,
3427 .log_details = btf_func_proto_log,
3428 .show = btf_df_show,
3429};
3430
3431static s32 btf_func_check_meta(struct btf_verifier_env *env,
3432 const struct btf_type *t,
3433 u32 meta_left)
3434{
3435 if (!t->name_off ||
3436 !btf_name_valid_identifier(env->btf, t->name_off)) {
3437 btf_verifier_log_type(env, t, "Invalid name");
3438 return -EINVAL;
3439 }
3440
3441 if (btf_type_vlen(t) > BTF_FUNC_GLOBAL) {
3442 btf_verifier_log_type(env, t, "Invalid func linkage");
3443 return -EINVAL;
3444 }
3445
3446 if (btf_type_kflag(t)) {
3447 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3448 return -EINVAL;
3449 }
3450
3451 btf_verifier_log_type(env, t, NULL);
3452
3453 return 0;
3454}
3455
3456static struct btf_kind_operations func_ops = {
3457 .check_meta = btf_func_check_meta,
3458 .resolve = btf_df_resolve,
3459 .check_member = btf_df_check_member,
3460 .check_kflag_member = btf_df_check_kflag_member,
3461 .log_details = btf_ref_type_log,
3462 .show = btf_df_show,
3463};
3464
3465static s32 btf_var_check_meta(struct btf_verifier_env *env,
3466 const struct btf_type *t,
3467 u32 meta_left)
3468{
3469 const struct btf_var *var;
3470 u32 meta_needed = sizeof(*var);
3471
3472 if (meta_left < meta_needed) {
3473 btf_verifier_log_basic(env, t,
3474 "meta_left:%u meta_needed:%u",
3475 meta_left, meta_needed);
3476 return -EINVAL;
3477 }
3478
3479 if (btf_type_vlen(t)) {
3480 btf_verifier_log_type(env, t, "vlen != 0");
3481 return -EINVAL;
3482 }
3483
3484 if (btf_type_kflag(t)) {
3485 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3486 return -EINVAL;
3487 }
3488
3489 if (!t->name_off ||
3490 !__btf_name_valid(env->btf, t->name_off, true)) {
3491 btf_verifier_log_type(env, t, "Invalid name");
3492 return -EINVAL;
3493 }
3494
3495 /* A var cannot be in type void */
3496 if (!t->type || !BTF_TYPE_ID_VALID(t->type)) {
3497 btf_verifier_log_type(env, t, "Invalid type_id");
3498 return -EINVAL;
3499 }
3500
3501 var = btf_type_var(t);
3502 if (var->linkage != BTF_VAR_STATIC &&
3503 var->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
3504 btf_verifier_log_type(env, t, "Linkage not supported");
3505 return -EINVAL;
3506 }
3507
3508 btf_verifier_log_type(env, t, NULL);
3509
3510 return meta_needed;
3511}
3512
3513static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t)
3514{
3515 const struct btf_var *var = btf_type_var(t);
3516
3517 btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage);
3518}
3519
3520static const struct btf_kind_operations var_ops = {
3521 .check_meta = btf_var_check_meta,
3522 .resolve = btf_var_resolve,
3523 .check_member = btf_df_check_member,
3524 .check_kflag_member = btf_df_check_kflag_member,
3525 .log_details = btf_var_log,
3526 .show = btf_var_show,
3527};
3528
3529static s32 btf_datasec_check_meta(struct btf_verifier_env *env,
3530 const struct btf_type *t,
3531 u32 meta_left)
3532{
3533 const struct btf_var_secinfo *vsi;
3534 u64 last_vsi_end_off = 0, sum = 0;
3535 u32 i, meta_needed;
3536
3537 meta_needed = btf_type_vlen(t) * sizeof(*vsi);
3538 if (meta_left < meta_needed) {
3539 btf_verifier_log_basic(env, t,
3540 "meta_left:%u meta_needed:%u",
3541 meta_left, meta_needed);
3542 return -EINVAL;
3543 }
3544
3545 if (!t->size) {
3546 btf_verifier_log_type(env, t, "size == 0");
3547 return -EINVAL;
3548 }
3549
3550 if (btf_type_kflag(t)) {
3551 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3552 return -EINVAL;
3553 }
3554
3555 if (!t->name_off ||
3556 !btf_name_valid_section(env->btf, t->name_off)) {
3557 btf_verifier_log_type(env, t, "Invalid name");
3558 return -EINVAL;
3559 }
3560
3561 btf_verifier_log_type(env, t, NULL);
3562
3563 for_each_vsi(i, t, vsi) {
3564 /* A var cannot be in type void */
3565 if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) {
3566 btf_verifier_log_vsi(env, t, vsi,
3567 "Invalid type_id");
3568 return -EINVAL;
3569 }
3570
3571 if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) {
3572 btf_verifier_log_vsi(env, t, vsi,
3573 "Invalid offset");
3574 return -EINVAL;
3575 }
3576
3577 if (!vsi->size || vsi->size > t->size) {
3578 btf_verifier_log_vsi(env, t, vsi,
3579 "Invalid size");
3580 return -EINVAL;
3581 }
3582
3583 last_vsi_end_off = vsi->offset + vsi->size;
3584 if (last_vsi_end_off > t->size) {
3585 btf_verifier_log_vsi(env, t, vsi,
3586 "Invalid offset+size");
3587 return -EINVAL;
3588 }
3589
3590 btf_verifier_log_vsi(env, t, vsi, NULL);
3591 sum += vsi->size;
3592 }
3593
3594 if (t->size < sum) {
3595 btf_verifier_log_type(env, t, "Invalid btf_info size");
3596 return -EINVAL;
3597 }
3598
3599 return meta_needed;
3600}
3601
3602static int btf_datasec_resolve(struct btf_verifier_env *env,
3603 const struct resolve_vertex *v)
3604{
3605 const struct btf_var_secinfo *vsi;
3606 struct btf *btf = env->btf;
3607 u16 i;
3608
3609 for_each_vsi_from(i, v->next_member, v->t, vsi) {
3610 u32 var_type_id = vsi->type, type_id, type_size = 0;
3611 const struct btf_type *var_type = btf_type_by_id(env->btf,
3612 var_type_id);
3613 if (!var_type || !btf_type_is_var(var_type)) {
3614 btf_verifier_log_vsi(env, v->t, vsi,
3615 "Not a VAR kind member");
3616 return -EINVAL;
3617 }
3618
3619 if (!env_type_is_resolve_sink(env, var_type) &&
3620 !env_type_is_resolved(env, var_type_id)) {
3621 env_stack_set_next_member(env, i + 1);
3622 return env_stack_push(env, var_type, var_type_id);
3623 }
3624
3625 type_id = var_type->type;
3626 if (!btf_type_id_size(btf, &type_id, &type_size)) {
3627 btf_verifier_log_vsi(env, v->t, vsi, "Invalid type");
3628 return -EINVAL;
3629 }
3630
3631 if (vsi->size < type_size) {
3632 btf_verifier_log_vsi(env, v->t, vsi, "Invalid size");
3633 return -EINVAL;
3634 }
3635 }
3636
3637 env_stack_pop_resolved(env, 0, 0);
3638 return 0;
3639}
3640
3641static void btf_datasec_log(struct btf_verifier_env *env,
3642 const struct btf_type *t)
3643{
3644 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3645}
3646
3647static void btf_datasec_show(const struct btf *btf,
3648 const struct btf_type *t, u32 type_id,
3649 void *data, u8 bits_offset,
3650 struct btf_show *show)
3651{
3652 const struct btf_var_secinfo *vsi;
3653 const struct btf_type *var;
3654 u32 i;
3655
3656 if (!btf_show_start_type(show, t, type_id, data))
3657 return;
3658
3659 btf_show_type_value(show, "section (\"%s\") = {",
3660 __btf_name_by_offset(btf, t->name_off));
3661 for_each_vsi(i, t, vsi) {
3662 var = btf_type_by_id(btf, vsi->type);
3663 if (i)
3664 btf_show(show, ",");
3665 btf_type_ops(var)->show(btf, var, vsi->type,
3666 data + vsi->offset, bits_offset, show);
3667 }
3668 btf_show_end_type(show);
3669}
3670
3671static const struct btf_kind_operations datasec_ops = {
3672 .check_meta = btf_datasec_check_meta,
3673 .resolve = btf_datasec_resolve,
3674 .check_member = btf_df_check_member,
3675 .check_kflag_member = btf_df_check_kflag_member,
3676 .log_details = btf_datasec_log,
3677 .show = btf_datasec_show,
3678};
3679
3680static s32 btf_float_check_meta(struct btf_verifier_env *env,
3681 const struct btf_type *t,
3682 u32 meta_left)
3683{
3684 if (btf_type_vlen(t)) {
3685 btf_verifier_log_type(env, t, "vlen != 0");
3686 return -EINVAL;
3687 }
3688
3689 if (btf_type_kflag(t)) {
3690 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3691 return -EINVAL;
3692 }
3693
3694 if (t->size != 2 && t->size != 4 && t->size != 8 && t->size != 12 &&
3695 t->size != 16) {
3696 btf_verifier_log_type(env, t, "Invalid type_size");
3697 return -EINVAL;
3698 }
3699
3700 btf_verifier_log_type(env, t, NULL);
3701
3702 return 0;
3703}
3704
3705static int btf_float_check_member(struct btf_verifier_env *env,
3706 const struct btf_type *struct_type,
3707 const struct btf_member *member,
3708 const struct btf_type *member_type)
3709{
3710 u64 start_offset_bytes;
3711 u64 end_offset_bytes;
3712 u64 misalign_bits;
3713 u64 align_bytes;
3714 u64 align_bits;
3715
3716 /* Different architectures have different alignment requirements, so
3717 * here we check only for the reasonable minimum. This way we ensure
3718 * that types after CO-RE can pass the kernel BTF verifier.
3719 */
3720 align_bytes = min_t(u64, sizeof(void *), member_type->size);
3721 align_bits = align_bytes * BITS_PER_BYTE;
3722 div64_u64_rem(member->offset, align_bits, &misalign_bits);
3723 if (misalign_bits) {
3724 btf_verifier_log_member(env, struct_type, member,
3725 "Member is not properly aligned");
3726 return -EINVAL;
3727 }
3728
3729 start_offset_bytes = member->offset / BITS_PER_BYTE;
3730 end_offset_bytes = start_offset_bytes + member_type->size;
3731 if (end_offset_bytes > struct_type->size) {
3732 btf_verifier_log_member(env, struct_type, member,
3733 "Member exceeds struct_size");
3734 return -EINVAL;
3735 }
3736
3737 return 0;
3738}
3739
3740static void btf_float_log(struct btf_verifier_env *env,
3741 const struct btf_type *t)
3742{
3743 btf_verifier_log(env, "size=%u", t->size);
3744}
3745
3746static const struct btf_kind_operations float_ops = {
3747 .check_meta = btf_float_check_meta,
3748 .resolve = btf_df_resolve,
3749 .check_member = btf_float_check_member,
3750 .check_kflag_member = btf_generic_check_kflag_member,
3751 .log_details = btf_float_log,
3752 .show = btf_df_show,
3753};
3754
3755static int btf_func_proto_check(struct btf_verifier_env *env,
3756 const struct btf_type *t)
3757{
3758 const struct btf_type *ret_type;
3759 const struct btf_param *args;
3760 const struct btf *btf;
3761 u16 nr_args, i;
3762 int err;
3763
3764 btf = env->btf;
3765 args = (const struct btf_param *)(t + 1);
3766 nr_args = btf_type_vlen(t);
3767
3768 /* Check func return type which could be "void" (t->type == 0) */
3769 if (t->type) {
3770 u32 ret_type_id = t->type;
3771
3772 ret_type = btf_type_by_id(btf, ret_type_id);
3773 if (!ret_type) {
3774 btf_verifier_log_type(env, t, "Invalid return type");
3775 return -EINVAL;
3776 }
3777
3778 if (btf_type_needs_resolve(ret_type) &&
3779 !env_type_is_resolved(env, ret_type_id)) {
3780 err = btf_resolve(env, ret_type, ret_type_id);
3781 if (err)
3782 return err;
3783 }
3784
3785 /* Ensure the return type is a type that has a size */
3786 if (!btf_type_id_size(btf, &ret_type_id, NULL)) {
3787 btf_verifier_log_type(env, t, "Invalid return type");
3788 return -EINVAL;
3789 }
3790 }
3791
3792 if (!nr_args)
3793 return 0;
3794
3795 /* Last func arg type_id could be 0 if it is a vararg */
3796 if (!args[nr_args - 1].type) {
3797 if (args[nr_args - 1].name_off) {
3798 btf_verifier_log_type(env, t, "Invalid arg#%u",
3799 nr_args);
3800 return -EINVAL;
3801 }
3802 nr_args--;
3803 }
3804
3805 err = 0;
3806 for (i = 0; i < nr_args; i++) {
3807 const struct btf_type *arg_type;
3808 u32 arg_type_id;
3809
3810 arg_type_id = args[i].type;
3811 arg_type = btf_type_by_id(btf, arg_type_id);
3812 if (!arg_type) {
3813 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
3814 err = -EINVAL;
3815 break;
3816 }
3817
3818 if (args[i].name_off &&
3819 (!btf_name_offset_valid(btf, args[i].name_off) ||
3820 !btf_name_valid_identifier(btf, args[i].name_off))) {
3821 btf_verifier_log_type(env, t,
3822 "Invalid arg#%u", i + 1);
3823 err = -EINVAL;
3824 break;
3825 }
3826
3827 if (btf_type_needs_resolve(arg_type) &&
3828 !env_type_is_resolved(env, arg_type_id)) {
3829 err = btf_resolve(env, arg_type, arg_type_id);
3830 if (err)
3831 break;
3832 }
3833
3834 if (!btf_type_id_size(btf, &arg_type_id, NULL)) {
3835 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
3836 err = -EINVAL;
3837 break;
3838 }
3839 }
3840
3841 return err;
3842}
3843
3844static int btf_func_check(struct btf_verifier_env *env,
3845 const struct btf_type *t)
3846{
3847 const struct btf_type *proto_type;
3848 const struct btf_param *args;
3849 const struct btf *btf;
3850 u16 nr_args, i;
3851
3852 btf = env->btf;
3853 proto_type = btf_type_by_id(btf, t->type);
3854
3855 if (!proto_type || !btf_type_is_func_proto(proto_type)) {
3856 btf_verifier_log_type(env, t, "Invalid type_id");
3857 return -EINVAL;
3858 }
3859
3860 args = (const struct btf_param *)(proto_type + 1);
3861 nr_args = btf_type_vlen(proto_type);
3862 for (i = 0; i < nr_args; i++) {
3863 if (!args[i].name_off && args[i].type) {
3864 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
3865 return -EINVAL;
3866 }
3867 }
3868
3869 return 0;
3870}
3871
3872static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
3873 [BTF_KIND_INT] = &int_ops,
3874 [BTF_KIND_PTR] = &ptr_ops,
3875 [BTF_KIND_ARRAY] = &array_ops,
3876 [BTF_KIND_STRUCT] = &struct_ops,
3877 [BTF_KIND_UNION] = &struct_ops,
3878 [BTF_KIND_ENUM] = &enum_ops,
3879 [BTF_KIND_FWD] = &fwd_ops,
3880 [BTF_KIND_TYPEDEF] = &modifier_ops,
3881 [BTF_KIND_VOLATILE] = &modifier_ops,
3882 [BTF_KIND_CONST] = &modifier_ops,
3883 [BTF_KIND_RESTRICT] = &modifier_ops,
3884 [BTF_KIND_FUNC] = &func_ops,
3885 [BTF_KIND_FUNC_PROTO] = &func_proto_ops,
3886 [BTF_KIND_VAR] = &var_ops,
3887 [BTF_KIND_DATASEC] = &datasec_ops,
3888 [BTF_KIND_FLOAT] = &float_ops,
3889};
3890
3891static s32 btf_check_meta(struct btf_verifier_env *env,
3892 const struct btf_type *t,
3893 u32 meta_left)
3894{
3895 u32 saved_meta_left = meta_left;
3896 s32 var_meta_size;
3897
3898 if (meta_left < sizeof(*t)) {
3899 btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
3900 env->log_type_id, meta_left, sizeof(*t));
3901 return -EINVAL;
3902 }
3903 meta_left -= sizeof(*t);
3904
3905 if (t->info & ~BTF_INFO_MASK) {
3906 btf_verifier_log(env, "[%u] Invalid btf_info:%x",
3907 env->log_type_id, t->info);
3908 return -EINVAL;
3909 }
3910
3911 if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
3912 BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
3913 btf_verifier_log(env, "[%u] Invalid kind:%u",
3914 env->log_type_id, BTF_INFO_KIND(t->info));
3915 return -EINVAL;
3916 }
3917
3918 if (!btf_name_offset_valid(env->btf, t->name_off)) {
3919 btf_verifier_log(env, "[%u] Invalid name_offset:%u",
3920 env->log_type_id, t->name_off);
3921 return -EINVAL;
3922 }
3923
3924 var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
3925 if (var_meta_size < 0)
3926 return var_meta_size;
3927
3928 meta_left -= var_meta_size;
3929
3930 return saved_meta_left - meta_left;
3931}
3932
3933static int btf_check_all_metas(struct btf_verifier_env *env)
3934{
3935 struct btf *btf = env->btf;
3936 struct btf_header *hdr;
3937 void *cur, *end;
3938
3939 hdr = &btf->hdr;
3940 cur = btf->nohdr_data + hdr->type_off;
3941 end = cur + hdr->type_len;
3942
3943 env->log_type_id = btf->base_btf ? btf->start_id : 1;
3944 while (cur < end) {
3945 struct btf_type *t = cur;
3946 s32 meta_size;
3947
3948 meta_size = btf_check_meta(env, t, end - cur);
3949 if (meta_size < 0)
3950 return meta_size;
3951
3952 btf_add_type(env, t);
3953 cur += meta_size;
3954 env->log_type_id++;
3955 }
3956
3957 return 0;
3958}
3959
3960static bool btf_resolve_valid(struct btf_verifier_env *env,
3961 const struct btf_type *t,
3962 u32 type_id)
3963{
3964 struct btf *btf = env->btf;
3965
3966 if (!env_type_is_resolved(env, type_id))
3967 return false;
3968
3969 if (btf_type_is_struct(t) || btf_type_is_datasec(t))
3970 return !btf_resolved_type_id(btf, type_id) &&
3971 !btf_resolved_type_size(btf, type_id);
3972
3973 if (btf_type_is_modifier(t) || btf_type_is_ptr(t) ||
3974 btf_type_is_var(t)) {
3975 t = btf_type_id_resolve(btf, &type_id);
3976 return t &&
3977 !btf_type_is_modifier(t) &&
3978 !btf_type_is_var(t) &&
3979 !btf_type_is_datasec(t);
3980 }
3981
3982 if (btf_type_is_array(t)) {
3983 const struct btf_array *array = btf_type_array(t);
3984 const struct btf_type *elem_type;
3985 u32 elem_type_id = array->type;
3986 u32 elem_size;
3987
3988 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
3989 return elem_type && !btf_type_is_modifier(elem_type) &&
3990 (array->nelems * elem_size ==
3991 btf_resolved_type_size(btf, type_id));
3992 }
3993
3994 return false;
3995}
3996
3997static int btf_resolve(struct btf_verifier_env *env,
3998 const struct btf_type *t, u32 type_id)
3999{
4000 u32 save_log_type_id = env->log_type_id;
4001 const struct resolve_vertex *v;
4002 int err = 0;
4003
4004 env->resolve_mode = RESOLVE_TBD;
4005 env_stack_push(env, t, type_id);
4006 while (!err && (v = env_stack_peak(env))) {
4007 env->log_type_id = v->type_id;
4008 err = btf_type_ops(v->t)->resolve(env, v);
4009 }
4010
4011 env->log_type_id = type_id;
4012 if (err == -E2BIG) {
4013 btf_verifier_log_type(env, t,
4014 "Exceeded max resolving depth:%u",
4015 MAX_RESOLVE_DEPTH);
4016 } else if (err == -EEXIST) {
4017 btf_verifier_log_type(env, t, "Loop detected");
4018 }
4019
4020 /* Final sanity check */
4021 if (!err && !btf_resolve_valid(env, t, type_id)) {
4022 btf_verifier_log_type(env, t, "Invalid resolve state");
4023 err = -EINVAL;
4024 }
4025
4026 env->log_type_id = save_log_type_id;
4027 return err;
4028}
4029
4030static int btf_check_all_types(struct btf_verifier_env *env)
4031{
4032 struct btf *btf = env->btf;
4033 const struct btf_type *t;
4034 u32 type_id, i;
4035 int err;
4036
4037 err = env_resolve_init(env);
4038 if (err)
4039 return err;
4040
4041 env->phase++;
4042 for (i = btf->base_btf ? 0 : 1; i < btf->nr_types; i++) {
4043 type_id = btf->start_id + i;
4044 t = btf_type_by_id(btf, type_id);
4045
4046 env->log_type_id = type_id;
4047 if (btf_type_needs_resolve(t) &&
4048 !env_type_is_resolved(env, type_id)) {
4049 err = btf_resolve(env, t, type_id);
4050 if (err)
4051 return err;
4052 }
4053
4054 if (btf_type_is_func_proto(t)) {
4055 err = btf_func_proto_check(env, t);
4056 if (err)
4057 return err;
4058 }
4059
4060 if (btf_type_is_func(t)) {
4061 err = btf_func_check(env, t);
4062 if (err)
4063 return err;
4064 }
4065 }
4066
4067 return 0;
4068}
4069
4070static int btf_parse_type_sec(struct btf_verifier_env *env)
4071{
4072 const struct btf_header *hdr = &env->btf->hdr;
4073 int err;
4074
4075 /* Type section must align to 4 bytes */
4076 if (hdr->type_off & (sizeof(u32) - 1)) {
4077 btf_verifier_log(env, "Unaligned type_off");
4078 return -EINVAL;
4079 }
4080
4081 if (!env->btf->base_btf && !hdr->type_len) {
4082 btf_verifier_log(env, "No type found");
4083 return -EINVAL;
4084 }
4085
4086 err = btf_check_all_metas(env);
4087 if (err)
4088 return err;
4089
4090 return btf_check_all_types(env);
4091}
4092
4093static int btf_parse_str_sec(struct btf_verifier_env *env)
4094{
4095 const struct btf_header *hdr;
4096 struct btf *btf = env->btf;
4097 const char *start, *end;
4098
4099 hdr = &btf->hdr;
4100 start = btf->nohdr_data + hdr->str_off;
4101 end = start + hdr->str_len;
4102
4103 if (end != btf->data + btf->data_size) {
4104 btf_verifier_log(env, "String section is not at the end");
4105 return -EINVAL;
4106 }
4107
4108 btf->strings = start;
4109
4110 if (btf->base_btf && !hdr->str_len)
4111 return 0;
4112 if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET || end[-1]) {
4113 btf_verifier_log(env, "Invalid string section");
4114 return -EINVAL;
4115 }
4116 if (!btf->base_btf && start[0]) {
4117 btf_verifier_log(env, "Invalid string section");
4118 return -EINVAL;
4119 }
4120
4121 return 0;
4122}
4123
4124static const size_t btf_sec_info_offset[] = {
4125 offsetof(struct btf_header, type_off),
4126 offsetof(struct btf_header, str_off),
4127};
4128
4129static int btf_sec_info_cmp(const void *a, const void *b)
4130{
4131 const struct btf_sec_info *x = a;
4132 const struct btf_sec_info *y = b;
4133
4134 return (int)(x->off - y->off) ? : (int)(x->len - y->len);
4135}
4136
4137static int btf_check_sec_info(struct btf_verifier_env *env,
4138 u32 btf_data_size)
4139{
4140 struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
4141 u32 total, expected_total, i;
4142 const struct btf_header *hdr;
4143 const struct btf *btf;
4144
4145 btf = env->btf;
4146 hdr = &btf->hdr;
4147
4148 /* Populate the secs from hdr */
4149 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
4150 secs[i] = *(struct btf_sec_info *)((void *)hdr +
4151 btf_sec_info_offset[i]);
4152
4153 sort(secs, ARRAY_SIZE(btf_sec_info_offset),
4154 sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
4155
4156 /* Check for gaps and overlap among sections */
4157 total = 0;
4158 expected_total = btf_data_size - hdr->hdr_len;
4159 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
4160 if (expected_total < secs[i].off) {
4161 btf_verifier_log(env, "Invalid section offset");
4162 return -EINVAL;
4163 }
4164 if (total < secs[i].off) {
4165 /* gap */
4166 btf_verifier_log(env, "Unsupported section found");
4167 return -EINVAL;
4168 }
4169 if (total > secs[i].off) {
4170 btf_verifier_log(env, "Section overlap found");
4171 return -EINVAL;
4172 }
4173 if (expected_total - total < secs[i].len) {
4174 btf_verifier_log(env,
4175 "Total section length too long");
4176 return -EINVAL;
4177 }
4178 total += secs[i].len;
4179 }
4180
4181 /* There is data other than hdr and known sections */
4182 if (expected_total != total) {
4183 btf_verifier_log(env, "Unsupported section found");
4184 return -EINVAL;
4185 }
4186
4187 return 0;
4188}
4189
4190static int btf_parse_hdr(struct btf_verifier_env *env)
4191{
4192 u32 hdr_len, hdr_copy, btf_data_size;
4193 const struct btf_header *hdr;
4194 struct btf *btf;
4195 int err;
4196
4197 btf = env->btf;
4198 btf_data_size = btf->data_size;
4199
4200 if (btf_data_size <
4201 offsetof(struct btf_header, hdr_len) + sizeof(hdr->hdr_len)) {
4202 btf_verifier_log(env, "hdr_len not found");
4203 return -EINVAL;
4204 }
4205
4206 hdr = btf->data;
4207 hdr_len = hdr->hdr_len;
4208 if (btf_data_size < hdr_len) {
4209 btf_verifier_log(env, "btf_header not found");
4210 return -EINVAL;
4211 }
4212
4213 /* Ensure the unsupported header fields are zero */
4214 if (hdr_len > sizeof(btf->hdr)) {
4215 u8 *expected_zero = btf->data + sizeof(btf->hdr);
4216 u8 *end = btf->data + hdr_len;
4217
4218 for (; expected_zero < end; expected_zero++) {
4219 if (*expected_zero) {
4220 btf_verifier_log(env, "Unsupported btf_header");
4221 return -E2BIG;
4222 }
4223 }
4224 }
4225
4226 hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
4227 memcpy(&btf->hdr, btf->data, hdr_copy);
4228
4229 hdr = &btf->hdr;
4230
4231 btf_verifier_log_hdr(env, btf_data_size);
4232
4233 if (hdr->magic != BTF_MAGIC) {
4234 btf_verifier_log(env, "Invalid magic");
4235 return -EINVAL;
4236 }
4237
4238 if (hdr->version != BTF_VERSION) {
4239 btf_verifier_log(env, "Unsupported version");
4240 return -ENOTSUPP;
4241 }
4242
4243 if (hdr->flags) {
4244 btf_verifier_log(env, "Unsupported flags");
4245 return -ENOTSUPP;
4246 }
4247
4248 if (!btf->base_btf && btf_data_size == hdr->hdr_len) {
4249 btf_verifier_log(env, "No data");
4250 return -EINVAL;
4251 }
4252
4253 err = btf_check_sec_info(env, btf_data_size);
4254 if (err)
4255 return err;
4256
4257 return 0;
4258}
4259
4260static struct btf *btf_parse(bpfptr_t btf_data, u32 btf_data_size,
4261 u32 log_level, char __user *log_ubuf, u32 log_size)
4262{
4263 struct btf_verifier_env *env = NULL;
4264 struct bpf_verifier_log *log;
4265 struct btf *btf = NULL;
4266 u8 *data;
4267 int err;
4268
4269 if (btf_data_size > BTF_MAX_SIZE)
4270 return ERR_PTR(-E2BIG);
4271
4272 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
4273 if (!env)
4274 return ERR_PTR(-ENOMEM);
4275
4276 log = &env->log;
4277 if (log_level || log_ubuf || log_size) {
4278 /* user requested verbose verifier output
4279 * and supplied buffer to store the verification trace
4280 */
4281 log->level = log_level;
4282 log->ubuf = log_ubuf;
4283 log->len_total = log_size;
4284
4285 /* log attributes have to be sane */
4286 if (log->len_total < 128 || log->len_total > UINT_MAX >> 8 ||
4287 !log->level || !log->ubuf) {
4288 err = -EINVAL;
4289 goto errout;
4290 }
4291 }
4292
4293 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
4294 if (!btf) {
4295 err = -ENOMEM;
4296 goto errout;
4297 }
4298 env->btf = btf;
4299
4300 data = kvmalloc(btf_data_size, GFP_KERNEL | __GFP_NOWARN);
4301 if (!data) {
4302 err = -ENOMEM;
4303 goto errout;
4304 }
4305
4306 btf->data = data;
4307 btf->data_size = btf_data_size;
4308
4309 if (copy_from_bpfptr(data, btf_data, btf_data_size)) {
4310 err = -EFAULT;
4311 goto errout;
4312 }
4313
4314 err = btf_parse_hdr(env);
4315 if (err)
4316 goto errout;
4317
4318 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
4319
4320 err = btf_parse_str_sec(env);
4321 if (err)
4322 goto errout;
4323
4324 err = btf_parse_type_sec(env);
4325 if (err)
4326 goto errout;
4327
4328 if (log->level && bpf_verifier_log_full(log)) {
4329 err = -ENOSPC;
4330 goto errout;
4331 }
4332
4333 btf_verifier_env_free(env);
4334 refcount_set(&btf->refcnt, 1);
4335 return btf;
4336
4337errout:
4338 btf_verifier_env_free(env);
4339 if (btf)
4340 btf_free(btf);
4341 return ERR_PTR(err);
4342}
4343
4344extern char __weak __start_BTF[];
4345extern char __weak __stop_BTF[];
4346extern struct btf *btf_vmlinux;
4347
4348#define BPF_MAP_TYPE(_id, _ops)
4349#define BPF_LINK_TYPE(_id, _name)
4350static union {
4351 struct bpf_ctx_convert {
4352#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
4353 prog_ctx_type _id##_prog; \
4354 kern_ctx_type _id##_kern;
4355#include <linux/bpf_types.h>
4356#undef BPF_PROG_TYPE
4357 } *__t;
4358 /* 't' is written once under lock. Read many times. */
4359 const struct btf_type *t;
4360} bpf_ctx_convert;
4361enum {
4362#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
4363 __ctx_convert##_id,
4364#include <linux/bpf_types.h>
4365#undef BPF_PROG_TYPE
4366 __ctx_convert_unused, /* to avoid empty enum in extreme .config */
4367};
4368static u8 bpf_ctx_convert_map[] = {
4369#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
4370 [_id] = __ctx_convert##_id,
4371#include <linux/bpf_types.h>
4372#undef BPF_PROG_TYPE
4373 0, /* avoid empty array */
4374};
4375#undef BPF_MAP_TYPE
4376#undef BPF_LINK_TYPE
4377
4378static const struct btf_member *
4379btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
4380 const struct btf_type *t, enum bpf_prog_type prog_type,
4381 int arg)
4382{
4383 const struct btf_type *conv_struct;
4384 const struct btf_type *ctx_struct;
4385 const struct btf_member *ctx_type;
4386 const char *tname, *ctx_tname;
4387
4388 conv_struct = bpf_ctx_convert.t;
4389 if (!conv_struct) {
4390 bpf_log(log, "btf_vmlinux is malformed\n");
4391 return NULL;
4392 }
4393 t = btf_type_by_id(btf, t->type);
4394 while (btf_type_is_modifier(t))
4395 t = btf_type_by_id(btf, t->type);
4396 if (!btf_type_is_struct(t)) {
4397 /* Only pointer to struct is supported for now.
4398 * That means that BPF_PROG_TYPE_TRACEPOINT with BTF
4399 * is not supported yet.
4400 * BPF_PROG_TYPE_RAW_TRACEPOINT is fine.
4401 */
4402 return NULL;
4403 }
4404 tname = btf_name_by_offset(btf, t->name_off);
4405 if (!tname) {
4406 bpf_log(log, "arg#%d struct doesn't have a name\n", arg);
4407 return NULL;
4408 }
4409 /* prog_type is valid bpf program type. No need for bounds check. */
4410 ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2;
4411 /* ctx_struct is a pointer to prog_ctx_type in vmlinux.
4412 * Like 'struct __sk_buff'
4413 */
4414 ctx_struct = btf_type_by_id(btf_vmlinux, ctx_type->type);
4415 if (!ctx_struct)
4416 /* should not happen */
4417 return NULL;
4418 ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_struct->name_off);
4419 if (!ctx_tname) {
4420 /* should not happen */
4421 bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n");
4422 return NULL;
4423 }
4424 /* only compare that prog's ctx type name is the same as
4425 * kernel expects. No need to compare field by field.
4426 * It's ok for bpf prog to do:
4427 * struct __sk_buff {};
4428 * int socket_filter_bpf_prog(struct __sk_buff *skb)
4429 * { // no fields of skb are ever used }
4430 */
4431 if (strcmp(ctx_tname, tname))
4432 return NULL;
4433 return ctx_type;
4434}
4435
4436static const struct bpf_map_ops * const btf_vmlinux_map_ops[] = {
4437#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type)
4438#define BPF_LINK_TYPE(_id, _name)
4439#define BPF_MAP_TYPE(_id, _ops) \
4440 [_id] = &_ops,
4441#include <linux/bpf_types.h>
4442#undef BPF_PROG_TYPE
4443#undef BPF_LINK_TYPE
4444#undef BPF_MAP_TYPE
4445};
4446
4447static int btf_vmlinux_map_ids_init(const struct btf *btf,
4448 struct bpf_verifier_log *log)
4449{
4450 const struct bpf_map_ops *ops;
4451 int i, btf_id;
4452
4453 for (i = 0; i < ARRAY_SIZE(btf_vmlinux_map_ops); ++i) {
4454 ops = btf_vmlinux_map_ops[i];
4455 if (!ops || (!ops->map_btf_name && !ops->map_btf_id))
4456 continue;
4457 if (!ops->map_btf_name || !ops->map_btf_id) {
4458 bpf_log(log, "map type %d is misconfigured\n", i);
4459 return -EINVAL;
4460 }
4461 btf_id = btf_find_by_name_kind(btf, ops->map_btf_name,
4462 BTF_KIND_STRUCT);
4463 if (btf_id < 0)
4464 return btf_id;
4465 *ops->map_btf_id = btf_id;
4466 }
4467
4468 return 0;
4469}
4470
4471static int btf_translate_to_vmlinux(struct bpf_verifier_log *log,
4472 struct btf *btf,
4473 const struct btf_type *t,
4474 enum bpf_prog_type prog_type,
4475 int arg)
4476{
4477 const struct btf_member *prog_ctx_type, *kern_ctx_type;
4478
4479 prog_ctx_type = btf_get_prog_ctx_type(log, btf, t, prog_type, arg);
4480 if (!prog_ctx_type)
4481 return -ENOENT;
4482 kern_ctx_type = prog_ctx_type + 1;
4483 return kern_ctx_type->type;
4484}
4485
4486BTF_ID_LIST(bpf_ctx_convert_btf_id)
4487BTF_ID(struct, bpf_ctx_convert)
4488
4489struct btf *btf_parse_vmlinux(void)
4490{
4491 struct btf_verifier_env *env = NULL;
4492 struct bpf_verifier_log *log;
4493 struct btf *btf = NULL;
4494 int err;
4495
4496 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
4497 if (!env)
4498 return ERR_PTR(-ENOMEM);
4499
4500 log = &env->log;
4501 log->level = BPF_LOG_KERNEL;
4502
4503 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
4504 if (!btf) {
4505 err = -ENOMEM;
4506 goto errout;
4507 }
4508 env->btf = btf;
4509
4510 btf->data = __start_BTF;
4511 btf->data_size = __stop_BTF - __start_BTF;
4512 btf->kernel_btf = true;
4513 snprintf(btf->name, sizeof(btf->name), "vmlinux");
4514
4515 err = btf_parse_hdr(env);
4516 if (err)
4517 goto errout;
4518
4519 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
4520
4521 err = btf_parse_str_sec(env);
4522 if (err)
4523 goto errout;
4524
4525 err = btf_check_all_metas(env);
4526 if (err)
4527 goto errout;
4528
4529 /* btf_parse_vmlinux() runs under bpf_verifier_lock */
4530 bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]);
4531
4532 /* find bpf map structs for map_ptr access checking */
4533 err = btf_vmlinux_map_ids_init(btf, log);
4534 if (err < 0)
4535 goto errout;
4536
4537 bpf_struct_ops_init(btf, log);
4538
4539 refcount_set(&btf->refcnt, 1);
4540
4541 err = btf_alloc_id(btf);
4542 if (err)
4543 goto errout;
4544
4545 btf_verifier_env_free(env);
4546 return btf;
4547
4548errout:
4549 btf_verifier_env_free(env);
4550 if (btf) {
4551 kvfree(btf->types);
4552 kfree(btf);
4553 }
4554 return ERR_PTR(err);
4555}
4556
4557#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
4558
4559static struct btf *btf_parse_module(const char *module_name, const void *data, unsigned int data_size)
4560{
4561 struct btf_verifier_env *env = NULL;
4562 struct bpf_verifier_log *log;
4563 struct btf *btf = NULL, *base_btf;
4564 int err;
4565
4566 base_btf = bpf_get_btf_vmlinux();
4567 if (IS_ERR(base_btf))
4568 return base_btf;
4569 if (!base_btf)
4570 return ERR_PTR(-EINVAL);
4571
4572 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
4573 if (!env)
4574 return ERR_PTR(-ENOMEM);
4575
4576 log = &env->log;
4577 log->level = BPF_LOG_KERNEL;
4578
4579 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
4580 if (!btf) {
4581 err = -ENOMEM;
4582 goto errout;
4583 }
4584 env->btf = btf;
4585
4586 btf->base_btf = base_btf;
4587 btf->start_id = base_btf->nr_types;
4588 btf->start_str_off = base_btf->hdr.str_len;
4589 btf->kernel_btf = true;
4590 snprintf(btf->name, sizeof(btf->name), "%s", module_name);
4591
4592 btf->data = kvmalloc(data_size, GFP_KERNEL | __GFP_NOWARN);
4593 if (!btf->data) {
4594 err = -ENOMEM;
4595 goto errout;
4596 }
4597 memcpy(btf->data, data, data_size);
4598 btf->data_size = data_size;
4599
4600 err = btf_parse_hdr(env);
4601 if (err)
4602 goto errout;
4603
4604 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
4605
4606 err = btf_parse_str_sec(env);
4607 if (err)
4608 goto errout;
4609
4610 err = btf_check_all_metas(env);
4611 if (err)
4612 goto errout;
4613
4614 btf_verifier_env_free(env);
4615 refcount_set(&btf->refcnt, 1);
4616 return btf;
4617
4618errout:
4619 btf_verifier_env_free(env);
4620 if (btf) {
4621 kvfree(btf->data);
4622 kvfree(btf->types);
4623 kfree(btf);
4624 }
4625 return ERR_PTR(err);
4626}
4627
4628#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
4629
4630struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog)
4631{
4632 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
4633
4634 if (tgt_prog)
4635 return tgt_prog->aux->btf;
4636 else
4637 return prog->aux->attach_btf;
4638}
4639
4640static bool is_string_ptr(struct btf *btf, const struct btf_type *t)
4641{
4642 /* t comes in already as a pointer */
4643 t = btf_type_by_id(btf, t->type);
4644
4645 /* allow const */
4646 if (BTF_INFO_KIND(t->info) == BTF_KIND_CONST)
4647 t = btf_type_by_id(btf, t->type);
4648
4649 /* char, signed char, unsigned char */
4650 return btf_type_is_int(t) && t->size == 1;
4651}
4652
4653bool btf_ctx_access(int off, int size, enum bpf_access_type type,
4654 const struct bpf_prog *prog,
4655 struct bpf_insn_access_aux *info)
4656{
4657 const struct btf_type *t = prog->aux->attach_func_proto;
4658 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
4659 struct btf *btf = bpf_prog_get_target_btf(prog);
4660 const char *tname = prog->aux->attach_func_name;
4661 struct bpf_verifier_log *log = info->log;
4662 const struct btf_param *args;
4663 u32 nr_args, arg;
4664 int i, ret;
4665
4666 if (off % 8) {
4667 bpf_log(log, "func '%s' offset %d is not multiple of 8\n",
4668 tname, off);
4669 return false;
4670 }
4671 arg = off / 8;
4672 args = (const struct btf_param *)(t + 1);
4673 /* if (t == NULL) Fall back to default BPF prog with
4674 * MAX_BPF_FUNC_REG_ARGS u64 arguments.
4675 */
4676 nr_args = t ? btf_type_vlen(t) : MAX_BPF_FUNC_REG_ARGS;
4677 if (prog->aux->attach_btf_trace) {
4678 /* skip first 'void *__data' argument in btf_trace_##name typedef */
4679 args++;
4680 nr_args--;
4681 }
4682
4683 if (arg > nr_args) {
4684 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
4685 tname, arg + 1);
4686 return false;
4687 }
4688
4689 if (arg == nr_args) {
4690 switch (prog->expected_attach_type) {
4691 case BPF_LSM_MAC:
4692 case BPF_TRACE_FEXIT:
4693 /* When LSM programs are attached to void LSM hooks
4694 * they use FEXIT trampolines and when attached to
4695 * int LSM hooks, they use MODIFY_RETURN trampolines.
4696 *
4697 * While the LSM programs are BPF_MODIFY_RETURN-like
4698 * the check:
4699 *
4700 * if (ret_type != 'int')
4701 * return -EINVAL;
4702 *
4703 * is _not_ done here. This is still safe as LSM hooks
4704 * have only void and int return types.
4705 */
4706 if (!t)
4707 return true;
4708 t = btf_type_by_id(btf, t->type);
4709 break;
4710 case BPF_MODIFY_RETURN:
4711 /* For now the BPF_MODIFY_RETURN can only be attached to
4712 * functions that return an int.
4713 */
4714 if (!t)
4715 return false;
4716
4717 t = btf_type_skip_modifiers(btf, t->type, NULL);
4718 if (!btf_type_is_small_int(t)) {
4719 bpf_log(log,
4720 "ret type %s not allowed for fmod_ret\n",
4721 btf_kind_str[BTF_INFO_KIND(t->info)]);
4722 return false;
4723 }
4724 break;
4725 default:
4726 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
4727 tname, arg + 1);
4728 return false;
4729 }
4730 } else {
4731 if (!t)
4732 /* Default prog with MAX_BPF_FUNC_REG_ARGS args */
4733 return true;
4734 t = btf_type_by_id(btf, args[arg].type);
4735 }
4736
4737 /* skip modifiers */
4738 while (btf_type_is_modifier(t))
4739 t = btf_type_by_id(btf, t->type);
4740 if (btf_type_is_small_int(t) || btf_type_is_enum(t))
4741 /* accessing a scalar */
4742 return true;
4743 if (!btf_type_is_ptr(t)) {
4744 bpf_log(log,
4745 "func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n",
4746 tname, arg,
4747 __btf_name_by_offset(btf, t->name_off),
4748 btf_kind_str[BTF_INFO_KIND(t->info)]);
4749 return false;
4750 }
4751
4752 /* check for PTR_TO_RDONLY_BUF_OR_NULL or PTR_TO_RDWR_BUF_OR_NULL */
4753 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
4754 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
4755
4756 if (ctx_arg_info->offset == off &&
4757 (ctx_arg_info->reg_type == PTR_TO_RDONLY_BUF_OR_NULL ||
4758 ctx_arg_info->reg_type == PTR_TO_RDWR_BUF_OR_NULL)) {
4759 info->reg_type = ctx_arg_info->reg_type;
4760 return true;
4761 }
4762 }
4763
4764 if (t->type == 0)
4765 /* This is a pointer to void.
4766 * It is the same as scalar from the verifier safety pov.
4767 * No further pointer walking is allowed.
4768 */
4769 return true;
4770
4771 if (is_string_ptr(btf, t))
4772 return true;
4773
4774 /* this is a pointer to another type */
4775 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
4776 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
4777
4778 if (ctx_arg_info->offset == off) {
4779 info->reg_type = ctx_arg_info->reg_type;
4780 info->btf = btf_vmlinux;
4781 info->btf_id = ctx_arg_info->btf_id;
4782 return true;
4783 }
4784 }
4785
4786 info->reg_type = PTR_TO_BTF_ID;
4787 if (tgt_prog) {
4788 enum bpf_prog_type tgt_type;
4789
4790 if (tgt_prog->type == BPF_PROG_TYPE_EXT)
4791 tgt_type = tgt_prog->aux->saved_dst_prog_type;
4792 else
4793 tgt_type = tgt_prog->type;
4794
4795 ret = btf_translate_to_vmlinux(log, btf, t, tgt_type, arg);
4796 if (ret > 0) {
4797 info->btf = btf_vmlinux;
4798 info->btf_id = ret;
4799 return true;
4800 } else {
4801 return false;
4802 }
4803 }
4804
4805 info->btf = btf;
4806 info->btf_id = t->type;
4807 t = btf_type_by_id(btf, t->type);
4808 /* skip modifiers */
4809 while (btf_type_is_modifier(t)) {
4810 info->btf_id = t->type;
4811 t = btf_type_by_id(btf, t->type);
4812 }
4813 if (!btf_type_is_struct(t)) {
4814 bpf_log(log,
4815 "func '%s' arg%d type %s is not a struct\n",
4816 tname, arg, btf_kind_str[BTF_INFO_KIND(t->info)]);
4817 return false;
4818 }
4819 bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n",
4820 tname, arg, info->btf_id, btf_kind_str[BTF_INFO_KIND(t->info)],
4821 __btf_name_by_offset(btf, t->name_off));
4822 return true;
4823}
4824
4825enum bpf_struct_walk_result {
4826 /* < 0 error */
4827 WALK_SCALAR = 0,
4828 WALK_PTR,
4829 WALK_STRUCT,
4830};
4831
4832static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf,
4833 const struct btf_type *t, int off, int size,
4834 u32 *next_btf_id)
4835{
4836 u32 i, moff, mtrue_end, msize = 0, total_nelems = 0;
4837 const struct btf_type *mtype, *elem_type = NULL;
4838 const struct btf_member *member;
4839 const char *tname, *mname;
4840 u32 vlen, elem_id, mid;
4841
4842again:
4843 tname = __btf_name_by_offset(btf, t->name_off);
4844 if (!btf_type_is_struct(t)) {
4845 bpf_log(log, "Type '%s' is not a struct\n", tname);
4846 return -EINVAL;
4847 }
4848
4849 vlen = btf_type_vlen(t);
4850 if (off + size > t->size) {
4851 /* If the last element is a variable size array, we may
4852 * need to relax the rule.
4853 */
4854 struct btf_array *array_elem;
4855
4856 if (vlen == 0)
4857 goto error;
4858
4859 member = btf_type_member(t) + vlen - 1;
4860 mtype = btf_type_skip_modifiers(btf, member->type,
4861 NULL);
4862 if (!btf_type_is_array(mtype))
4863 goto error;
4864
4865 array_elem = (struct btf_array *)(mtype + 1);
4866 if (array_elem->nelems != 0)
4867 goto error;
4868
4869 moff = btf_member_bit_offset(t, member) / 8;
4870 if (off < moff)
4871 goto error;
4872
4873 /* Only allow structure for now, can be relaxed for
4874 * other types later.
4875 */
4876 t = btf_type_skip_modifiers(btf, array_elem->type,
4877 NULL);
4878 if (!btf_type_is_struct(t))
4879 goto error;
4880
4881 off = (off - moff) % t->size;
4882 goto again;
4883
4884error:
4885 bpf_log(log, "access beyond struct %s at off %u size %u\n",
4886 tname, off, size);
4887 return -EACCES;
4888 }
4889
4890 for_each_member(i, t, member) {
4891 /* offset of the field in bytes */
4892 moff = btf_member_bit_offset(t, member) / 8;
4893 if (off + size <= moff)
4894 /* won't find anything, field is already too far */
4895 break;
4896
4897 if (btf_member_bitfield_size(t, member)) {
4898 u32 end_bit = btf_member_bit_offset(t, member) +
4899 btf_member_bitfield_size(t, member);
4900
4901 /* off <= moff instead of off == moff because clang
4902 * does not generate a BTF member for anonymous
4903 * bitfield like the ":16" here:
4904 * struct {
4905 * int :16;
4906 * int x:8;
4907 * };
4908 */
4909 if (off <= moff &&
4910 BITS_ROUNDUP_BYTES(end_bit) <= off + size)
4911 return WALK_SCALAR;
4912
4913 /* off may be accessing a following member
4914 *
4915 * or
4916 *
4917 * Doing partial access at either end of this
4918 * bitfield. Continue on this case also to
4919 * treat it as not accessing this bitfield
4920 * and eventually error out as field not
4921 * found to keep it simple.
4922 * It could be relaxed if there was a legit
4923 * partial access case later.
4924 */
4925 continue;
4926 }
4927
4928 /* In case of "off" is pointing to holes of a struct */
4929 if (off < moff)
4930 break;
4931
4932 /* type of the field */
4933 mid = member->type;
4934 mtype = btf_type_by_id(btf, member->type);
4935 mname = __btf_name_by_offset(btf, member->name_off);
4936
4937 mtype = __btf_resolve_size(btf, mtype, &msize,
4938 &elem_type, &elem_id, &total_nelems,
4939 &mid);
4940 if (IS_ERR(mtype)) {
4941 bpf_log(log, "field %s doesn't have size\n", mname);
4942 return -EFAULT;
4943 }
4944
4945 mtrue_end = moff + msize;
4946 if (off >= mtrue_end)
4947 /* no overlap with member, keep iterating */
4948 continue;
4949
4950 if (btf_type_is_array(mtype)) {
4951 u32 elem_idx;
4952
4953 /* __btf_resolve_size() above helps to
4954 * linearize a multi-dimensional array.
4955 *
4956 * The logic here is treating an array
4957 * in a struct as the following way:
4958 *
4959 * struct outer {
4960 * struct inner array[2][2];
4961 * };
4962 *
4963 * looks like:
4964 *
4965 * struct outer {
4966 * struct inner array_elem0;
4967 * struct inner array_elem1;
4968 * struct inner array_elem2;
4969 * struct inner array_elem3;
4970 * };
4971 *
4972 * When accessing outer->array[1][0], it moves
4973 * moff to "array_elem2", set mtype to
4974 * "struct inner", and msize also becomes
4975 * sizeof(struct inner). Then most of the
4976 * remaining logic will fall through without
4977 * caring the current member is an array or
4978 * not.
4979 *
4980 * Unlike mtype/msize/moff, mtrue_end does not
4981 * change. The naming difference ("_true") tells
4982 * that it is not always corresponding to
4983 * the current mtype/msize/moff.
4984 * It is the true end of the current
4985 * member (i.e. array in this case). That
4986 * will allow an int array to be accessed like
4987 * a scratch space,
4988 * i.e. allow access beyond the size of
4989 * the array's element as long as it is
4990 * within the mtrue_end boundary.
4991 */
4992
4993 /* skip empty array */
4994 if (moff == mtrue_end)
4995 continue;
4996
4997 msize /= total_nelems;
4998 elem_idx = (off - moff) / msize;
4999 moff += elem_idx * msize;
5000 mtype = elem_type;
5001 mid = elem_id;
5002 }
5003
5004 /* the 'off' we're looking for is either equal to start
5005 * of this field or inside of this struct
5006 */
5007 if (btf_type_is_struct(mtype)) {
5008 /* our field must be inside that union or struct */
5009 t = mtype;
5010
5011 /* return if the offset matches the member offset */
5012 if (off == moff) {
5013 *next_btf_id = mid;
5014 return WALK_STRUCT;
5015 }
5016
5017 /* adjust offset we're looking for */
5018 off -= moff;
5019 goto again;
5020 }
5021
5022 if (btf_type_is_ptr(mtype)) {
5023 const struct btf_type *stype;
5024 u32 id;
5025
5026 if (msize != size || off != moff) {
5027 bpf_log(log,
5028 "cannot access ptr member %s with moff %u in struct %s with off %u size %u\n",
5029 mname, moff, tname, off, size);
5030 return -EACCES;
5031 }
5032 stype = btf_type_skip_modifiers(btf, mtype->type, &id);
5033 if (btf_type_is_struct(stype)) {
5034 *next_btf_id = id;
5035 return WALK_PTR;
5036 }
5037 }
5038
5039 /* Allow more flexible access within an int as long as
5040 * it is within mtrue_end.
5041 * Since mtrue_end could be the end of an array,
5042 * that also allows using an array of int as a scratch
5043 * space. e.g. skb->cb[].
5044 */
5045 if (off + size > mtrue_end) {
5046 bpf_log(log,
5047 "access beyond the end of member %s (mend:%u) in struct %s with off %u size %u\n",
5048 mname, mtrue_end, tname, off, size);
5049 return -EACCES;
5050 }
5051
5052 return WALK_SCALAR;
5053 }
5054 bpf_log(log, "struct %s doesn't have field at offset %d\n", tname, off);
5055 return -EINVAL;
5056}
5057
5058int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf,
5059 const struct btf_type *t, int off, int size,
5060 enum bpf_access_type atype __maybe_unused,
5061 u32 *next_btf_id)
5062{
5063 int err;
5064 u32 id;
5065
5066 do {
5067 err = btf_struct_walk(log, btf, t, off, size, &id);
5068
5069 switch (err) {
5070 case WALK_PTR:
5071 /* If we found the pointer or scalar on t+off,
5072 * we're done.
5073 */
5074 *next_btf_id = id;
5075 return PTR_TO_BTF_ID;
5076 case WALK_SCALAR:
5077 return SCALAR_VALUE;
5078 case WALK_STRUCT:
5079 /* We found nested struct, so continue the search
5080 * by diving in it. At this point the offset is
5081 * aligned with the new type, so set it to 0.
5082 */
5083 t = btf_type_by_id(btf, id);
5084 off = 0;
5085 break;
5086 default:
5087 /* It's either error or unknown return value..
5088 * scream and leave.
5089 */
5090 if (WARN_ONCE(err > 0, "unknown btf_struct_walk return value"))
5091 return -EINVAL;
5092 return err;
5093 }
5094 } while (t);
5095
5096 return -EINVAL;
5097}
5098
5099/* Check that two BTF types, each specified as an BTF object + id, are exactly
5100 * the same. Trivial ID check is not enough due to module BTFs, because we can
5101 * end up with two different module BTFs, but IDs point to the common type in
5102 * vmlinux BTF.
5103 */
5104static bool btf_types_are_same(const struct btf *btf1, u32 id1,
5105 const struct btf *btf2, u32 id2)
5106{
5107 if (id1 != id2)
5108 return false;
5109 if (btf1 == btf2)
5110 return true;
5111 return btf_type_by_id(btf1, id1) == btf_type_by_id(btf2, id2);
5112}
5113
5114bool btf_struct_ids_match(struct bpf_verifier_log *log,
5115 const struct btf *btf, u32 id, int off,
5116 const struct btf *need_btf, u32 need_type_id)
5117{
5118 const struct btf_type *type;
5119 int err;
5120
5121 /* Are we already done? */
5122 if (off == 0 && btf_types_are_same(btf, id, need_btf, need_type_id))
5123 return true;
5124
5125again:
5126 type = btf_type_by_id(btf, id);
5127 if (!type)
5128 return false;
5129 err = btf_struct_walk(log, btf, type, off, 1, &id);
5130 if (err != WALK_STRUCT)
5131 return false;
5132
5133 /* We found nested struct object. If it matches
5134 * the requested ID, we're done. Otherwise let's
5135 * continue the search with offset 0 in the new
5136 * type.
5137 */
5138 if (!btf_types_are_same(btf, id, need_btf, need_type_id)) {
5139 off = 0;
5140 goto again;
5141 }
5142
5143 return true;
5144}
5145
5146static int __get_type_size(struct btf *btf, u32 btf_id,
5147 const struct btf_type **bad_type)
5148{
5149 const struct btf_type *t;
5150
5151 if (!btf_id)
5152 /* void */
5153 return 0;
5154 t = btf_type_by_id(btf, btf_id);
5155 while (t && btf_type_is_modifier(t))
5156 t = btf_type_by_id(btf, t->type);
5157 if (!t) {
5158 *bad_type = btf_type_by_id(btf, 0);
5159 return -EINVAL;
5160 }
5161 if (btf_type_is_ptr(t))
5162 /* kernel size of pointer. Not BPF's size of pointer*/
5163 return sizeof(void *);
5164 if (btf_type_is_int(t) || btf_type_is_enum(t))
5165 return t->size;
5166 *bad_type = t;
5167 return -EINVAL;
5168}
5169
5170int btf_distill_func_proto(struct bpf_verifier_log *log,
5171 struct btf *btf,
5172 const struct btf_type *func,
5173 const char *tname,
5174 struct btf_func_model *m)
5175{
5176 const struct btf_param *args;
5177 const struct btf_type *t;
5178 u32 i, nargs;
5179 int ret;
5180
5181 if (!func) {
5182 /* BTF function prototype doesn't match the verifier types.
5183 * Fall back to MAX_BPF_FUNC_REG_ARGS u64 args.
5184 */
5185 for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++)
5186 m->arg_size[i] = 8;
5187 m->ret_size = 8;
5188 m->nr_args = MAX_BPF_FUNC_REG_ARGS;
5189 return 0;
5190 }
5191 args = (const struct btf_param *)(func + 1);
5192 nargs = btf_type_vlen(func);
5193 if (nargs >= MAX_BPF_FUNC_ARGS) {
5194 bpf_log(log,
5195 "The function %s has %d arguments. Too many.\n",
5196 tname, nargs);
5197 return -EINVAL;
5198 }
5199 ret = __get_type_size(btf, func->type, &t);
5200 if (ret < 0) {
5201 bpf_log(log,
5202 "The function %s return type %s is unsupported.\n",
5203 tname, btf_kind_str[BTF_INFO_KIND(t->info)]);
5204 return -EINVAL;
5205 }
5206 m->ret_size = ret;
5207
5208 for (i = 0; i < nargs; i++) {
5209 if (i == nargs - 1 && args[i].type == 0) {
5210 bpf_log(log,
5211 "The function %s with variable args is unsupported.\n",
5212 tname);
5213 return -EINVAL;
5214 }
5215 ret = __get_type_size(btf, args[i].type, &t);
5216 if (ret < 0) {
5217 bpf_log(log,
5218 "The function %s arg%d type %s is unsupported.\n",
5219 tname, i, btf_kind_str[BTF_INFO_KIND(t->info)]);
5220 return -EINVAL;
5221 }
5222 if (ret == 0) {
5223 bpf_log(log,
5224 "The function %s has malformed void argument.\n",
5225 tname);
5226 return -EINVAL;
5227 }
5228 m->arg_size[i] = ret;
5229 }
5230 m->nr_args = nargs;
5231 return 0;
5232}
5233
5234/* Compare BTFs of two functions assuming only scalars and pointers to context.
5235 * t1 points to BTF_KIND_FUNC in btf1
5236 * t2 points to BTF_KIND_FUNC in btf2
5237 * Returns:
5238 * EINVAL - function prototype mismatch
5239 * EFAULT - verifier bug
5240 * 0 - 99% match. The last 1% is validated by the verifier.
5241 */
5242static int btf_check_func_type_match(struct bpf_verifier_log *log,
5243 struct btf *btf1, const struct btf_type *t1,
5244 struct btf *btf2, const struct btf_type *t2)
5245{
5246 const struct btf_param *args1, *args2;
5247 const char *fn1, *fn2, *s1, *s2;
5248 u32 nargs1, nargs2, i;
5249
5250 fn1 = btf_name_by_offset(btf1, t1->name_off);
5251 fn2 = btf_name_by_offset(btf2, t2->name_off);
5252
5253 if (btf_func_linkage(t1) != BTF_FUNC_GLOBAL) {
5254 bpf_log(log, "%s() is not a global function\n", fn1);
5255 return -EINVAL;
5256 }
5257 if (btf_func_linkage(t2) != BTF_FUNC_GLOBAL) {
5258 bpf_log(log, "%s() is not a global function\n", fn2);
5259 return -EINVAL;
5260 }
5261
5262 t1 = btf_type_by_id(btf1, t1->type);
5263 if (!t1 || !btf_type_is_func_proto(t1))
5264 return -EFAULT;
5265 t2 = btf_type_by_id(btf2, t2->type);
5266 if (!t2 || !btf_type_is_func_proto(t2))
5267 return -EFAULT;
5268
5269 args1 = (const struct btf_param *)(t1 + 1);
5270 nargs1 = btf_type_vlen(t1);
5271 args2 = (const struct btf_param *)(t2 + 1);
5272 nargs2 = btf_type_vlen(t2);
5273
5274 if (nargs1 != nargs2) {
5275 bpf_log(log, "%s() has %d args while %s() has %d args\n",
5276 fn1, nargs1, fn2, nargs2);
5277 return -EINVAL;
5278 }
5279
5280 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
5281 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
5282 if (t1->info != t2->info) {
5283 bpf_log(log,
5284 "Return type %s of %s() doesn't match type %s of %s()\n",
5285 btf_type_str(t1), fn1,
5286 btf_type_str(t2), fn2);
5287 return -EINVAL;
5288 }
5289
5290 for (i = 0; i < nargs1; i++) {
5291 t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL);
5292 t2 = btf_type_skip_modifiers(btf2, args2[i].type, NULL);
5293
5294 if (t1->info != t2->info) {
5295 bpf_log(log, "arg%d in %s() is %s while %s() has %s\n",
5296 i, fn1, btf_type_str(t1),
5297 fn2, btf_type_str(t2));
5298 return -EINVAL;
5299 }
5300 if (btf_type_has_size(t1) && t1->size != t2->size) {
5301 bpf_log(log,
5302 "arg%d in %s() has size %d while %s() has %d\n",
5303 i, fn1, t1->size,
5304 fn2, t2->size);
5305 return -EINVAL;
5306 }
5307
5308 /* global functions are validated with scalars and pointers
5309 * to context only. And only global functions can be replaced.
5310 * Hence type check only those types.
5311 */
5312 if (btf_type_is_int(t1) || btf_type_is_enum(t1))
5313 continue;
5314 if (!btf_type_is_ptr(t1)) {
5315 bpf_log(log,
5316 "arg%d in %s() has unrecognized type\n",
5317 i, fn1);
5318 return -EINVAL;
5319 }
5320 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
5321 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
5322 if (!btf_type_is_struct(t1)) {
5323 bpf_log(log,
5324 "arg%d in %s() is not a pointer to context\n",
5325 i, fn1);
5326 return -EINVAL;
5327 }
5328 if (!btf_type_is_struct(t2)) {
5329 bpf_log(log,
5330 "arg%d in %s() is not a pointer to context\n",
5331 i, fn2);
5332 return -EINVAL;
5333 }
5334 /* This is an optional check to make program writing easier.
5335 * Compare names of structs and report an error to the user.
5336 * btf_prepare_func_args() already checked that t2 struct
5337 * is a context type. btf_prepare_func_args() will check
5338 * later that t1 struct is a context type as well.
5339 */
5340 s1 = btf_name_by_offset(btf1, t1->name_off);
5341 s2 = btf_name_by_offset(btf2, t2->name_off);
5342 if (strcmp(s1, s2)) {
5343 bpf_log(log,
5344 "arg%d %s(struct %s *) doesn't match %s(struct %s *)\n",
5345 i, fn1, s1, fn2, s2);
5346 return -EINVAL;
5347 }
5348 }
5349 return 0;
5350}
5351
5352/* Compare BTFs of given program with BTF of target program */
5353int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
5354 struct btf *btf2, const struct btf_type *t2)
5355{
5356 struct btf *btf1 = prog->aux->btf;
5357 const struct btf_type *t1;
5358 u32 btf_id = 0;
5359
5360 if (!prog->aux->func_info) {
5361 bpf_log(log, "Program extension requires BTF\n");
5362 return -EINVAL;
5363 }
5364
5365 btf_id = prog->aux->func_info[0].type_id;
5366 if (!btf_id)
5367 return -EFAULT;
5368
5369 t1 = btf_type_by_id(btf1, btf_id);
5370 if (!t1 || !btf_type_is_func(t1))
5371 return -EFAULT;
5372
5373 return btf_check_func_type_match(log, btf1, t1, btf2, t2);
5374}
5375
5376static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = {
5377#ifdef CONFIG_NET
5378 [PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK],
5379 [PTR_TO_SOCK_COMMON] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
5380 [PTR_TO_TCP_SOCK] = &btf_sock_ids[BTF_SOCK_TYPE_TCP],
5381#endif
5382};
5383
5384static int btf_check_func_arg_match(struct bpf_verifier_env *env,
5385 const struct btf *btf, u32 func_id,
5386 struct bpf_reg_state *regs,
5387 bool ptr_to_mem_ok)
5388{
5389 struct bpf_verifier_log *log = &env->log;
5390 const char *func_name, *ref_tname;
5391 const struct btf_type *t, *ref_t;
5392 const struct btf_param *args;
5393 u32 i, nargs, ref_id;
5394
5395 t = btf_type_by_id(btf, func_id);
5396 if (!t || !btf_type_is_func(t)) {
5397 /* These checks were already done by the verifier while loading
5398 * struct bpf_func_info or in add_kfunc_call().
5399 */
5400 bpf_log(log, "BTF of func_id %u doesn't point to KIND_FUNC\n",
5401 func_id);
5402 return -EFAULT;
5403 }
5404 func_name = btf_name_by_offset(btf, t->name_off);
5405
5406 t = btf_type_by_id(btf, t->type);
5407 if (!t || !btf_type_is_func_proto(t)) {
5408 bpf_log(log, "Invalid BTF of func %s\n", func_name);
5409 return -EFAULT;
5410 }
5411 args = (const struct btf_param *)(t + 1);
5412 nargs = btf_type_vlen(t);
5413 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
5414 bpf_log(log, "Function %s has %d > %d args\n", func_name, nargs,
5415 MAX_BPF_FUNC_REG_ARGS);
5416 return -EINVAL;
5417 }
5418
5419 /* check that BTF function arguments match actual types that the
5420 * verifier sees.
5421 */
5422 for (i = 0; i < nargs; i++) {
5423 u32 regno = i + 1;
5424 struct bpf_reg_state *reg = ®s[regno];
5425
5426 t = btf_type_skip_modifiers(btf, args[i].type, NULL);
5427 if (btf_type_is_scalar(t)) {
5428 if (reg->type == SCALAR_VALUE)
5429 continue;
5430 bpf_log(log, "R%d is not a scalar\n", regno);
5431 return -EINVAL;
5432 }
5433
5434 if (!btf_type_is_ptr(t)) {
5435 bpf_log(log, "Unrecognized arg#%d type %s\n",
5436 i, btf_type_str(t));
5437 return -EINVAL;
5438 }
5439
5440 ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id);
5441 ref_tname = btf_name_by_offset(btf, ref_t->name_off);
5442 if (btf_is_kernel(btf)) {
5443 const struct btf_type *reg_ref_t;
5444 const struct btf *reg_btf;
5445 const char *reg_ref_tname;
5446 u32 reg_ref_id;
5447
5448 if (!btf_type_is_struct(ref_t)) {
5449 bpf_log(log, "kernel function %s args#%d pointer type %s %s is not supported\n",
5450 func_name, i, btf_type_str(ref_t),
5451 ref_tname);
5452 return -EINVAL;
5453 }
5454
5455 if (reg->type == PTR_TO_BTF_ID) {
5456 reg_btf = reg->btf;
5457 reg_ref_id = reg->btf_id;
5458 } else if (reg2btf_ids[reg->type]) {
5459 reg_btf = btf_vmlinux;
5460 reg_ref_id = *reg2btf_ids[reg->type];
5461 } else {
5462 bpf_log(log, "kernel function %s args#%d expected pointer to %s %s but R%d is not a pointer to btf_id\n",
5463 func_name, i,
5464 btf_type_str(ref_t), ref_tname, regno);
5465 return -EINVAL;
5466 }
5467
5468 reg_ref_t = btf_type_skip_modifiers(reg_btf, reg_ref_id,
5469 ®_ref_id);
5470 reg_ref_tname = btf_name_by_offset(reg_btf,
5471 reg_ref_t->name_off);
5472 if (!btf_struct_ids_match(log, reg_btf, reg_ref_id,
5473 reg->off, btf, ref_id)) {
5474 bpf_log(log, "kernel function %s args#%d expected pointer to %s %s but R%d has a pointer to %s %s\n",
5475 func_name, i,
5476 btf_type_str(ref_t), ref_tname,
5477 regno, btf_type_str(reg_ref_t),
5478 reg_ref_tname);
5479 return -EINVAL;
5480 }
5481 } else if (btf_get_prog_ctx_type(log, btf, t,
5482 env->prog->type, i)) {
5483 /* If function expects ctx type in BTF check that caller
5484 * is passing PTR_TO_CTX.
5485 */
5486 if (reg->type != PTR_TO_CTX) {
5487 bpf_log(log,
5488 "arg#%d expected pointer to ctx, but got %s\n",
5489 i, btf_type_str(t));
5490 return -EINVAL;
5491 }
5492 if (check_ctx_reg(env, reg, regno))
5493 return -EINVAL;
5494 } else if (ptr_to_mem_ok) {
5495 const struct btf_type *resolve_ret;
5496 u32 type_size;
5497
5498 resolve_ret = btf_resolve_size(btf, ref_t, &type_size);
5499 if (IS_ERR(resolve_ret)) {
5500 bpf_log(log,
5501 "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
5502 i, btf_type_str(ref_t), ref_tname,
5503 PTR_ERR(resolve_ret));
5504 return -EINVAL;
5505 }
5506
5507 if (check_mem_reg(env, reg, regno, type_size))
5508 return -EINVAL;
5509 } else {
5510 return -EINVAL;
5511 }
5512 }
5513
5514 return 0;
5515}
5516
5517/* Compare BTF of a function with given bpf_reg_state.
5518 * Returns:
5519 * EFAULT - there is a verifier bug. Abort verification.
5520 * EINVAL - there is a type mismatch or BTF is not available.
5521 * 0 - BTF matches with what bpf_reg_state expects.
5522 * Only PTR_TO_CTX and SCALAR_VALUE states are recognized.
5523 */
5524int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog,
5525 struct bpf_reg_state *regs)
5526{
5527 struct bpf_prog *prog = env->prog;
5528 struct btf *btf = prog->aux->btf;
5529 bool is_global;
5530 u32 btf_id;
5531 int err;
5532
5533 if (!prog->aux->func_info)
5534 return -EINVAL;
5535
5536 btf_id = prog->aux->func_info[subprog].type_id;
5537 if (!btf_id)
5538 return -EFAULT;
5539
5540 if (prog->aux->func_info_aux[subprog].unreliable)
5541 return -EINVAL;
5542
5543 is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
5544 err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global);
5545
5546 /* Compiler optimizations can remove arguments from static functions
5547 * or mismatched type can be passed into a global function.
5548 * In such cases mark the function as unreliable from BTF point of view.
5549 */
5550 if (err)
5551 prog->aux->func_info_aux[subprog].unreliable = true;
5552 return err;
5553}
5554
5555int btf_check_kfunc_arg_match(struct bpf_verifier_env *env,
5556 const struct btf *btf, u32 func_id,
5557 struct bpf_reg_state *regs)
5558{
5559 return btf_check_func_arg_match(env, btf, func_id, regs, false);
5560}
5561
5562/* Convert BTF of a function into bpf_reg_state if possible
5563 * Returns:
5564 * EFAULT - there is a verifier bug. Abort verification.
5565 * EINVAL - cannot convert BTF.
5566 * 0 - Successfully converted BTF into bpf_reg_state
5567 * (either PTR_TO_CTX or SCALAR_VALUE).
5568 */
5569int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog,
5570 struct bpf_reg_state *regs)
5571{
5572 struct bpf_verifier_log *log = &env->log;
5573 struct bpf_prog *prog = env->prog;
5574 enum bpf_prog_type prog_type = prog->type;
5575 struct btf *btf = prog->aux->btf;
5576 const struct btf_param *args;
5577 const struct btf_type *t, *ref_t;
5578 u32 i, nargs, btf_id;
5579 const char *tname;
5580
5581 if (!prog->aux->func_info ||
5582 prog->aux->func_info_aux[subprog].linkage != BTF_FUNC_GLOBAL) {
5583 bpf_log(log, "Verifier bug\n");
5584 return -EFAULT;
5585 }
5586
5587 btf_id = prog->aux->func_info[subprog].type_id;
5588 if (!btf_id) {
5589 bpf_log(log, "Global functions need valid BTF\n");
5590 return -EFAULT;
5591 }
5592
5593 t = btf_type_by_id(btf, btf_id);
5594 if (!t || !btf_type_is_func(t)) {
5595 /* These checks were already done by the verifier while loading
5596 * struct bpf_func_info
5597 */
5598 bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n",
5599 subprog);
5600 return -EFAULT;
5601 }
5602 tname = btf_name_by_offset(btf, t->name_off);
5603
5604 if (log->level & BPF_LOG_LEVEL)
5605 bpf_log(log, "Validating %s() func#%d...\n",
5606 tname, subprog);
5607
5608 if (prog->aux->func_info_aux[subprog].unreliable) {
5609 bpf_log(log, "Verifier bug in function %s()\n", tname);
5610 return -EFAULT;
5611 }
5612 if (prog_type == BPF_PROG_TYPE_EXT)
5613 prog_type = prog->aux->dst_prog->type;
5614
5615 t = btf_type_by_id(btf, t->type);
5616 if (!t || !btf_type_is_func_proto(t)) {
5617 bpf_log(log, "Invalid type of function %s()\n", tname);
5618 return -EFAULT;
5619 }
5620 args = (const struct btf_param *)(t + 1);
5621 nargs = btf_type_vlen(t);
5622 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
5623 bpf_log(log, "Global function %s() with %d > %d args. Buggy compiler.\n",
5624 tname, nargs, MAX_BPF_FUNC_REG_ARGS);
5625 return -EINVAL;
5626 }
5627 /* check that function returns int */
5628 t = btf_type_by_id(btf, t->type);
5629 while (btf_type_is_modifier(t))
5630 t = btf_type_by_id(btf, t->type);
5631 if (!btf_type_is_int(t) && !btf_type_is_enum(t)) {
5632 bpf_log(log,
5633 "Global function %s() doesn't return scalar. Only those are supported.\n",
5634 tname);
5635 return -EINVAL;
5636 }
5637 /* Convert BTF function arguments into verifier types.
5638 * Only PTR_TO_CTX and SCALAR are supported atm.
5639 */
5640 for (i = 0; i < nargs; i++) {
5641 struct bpf_reg_state *reg = ®s[i + 1];
5642
5643 t = btf_type_by_id(btf, args[i].type);
5644 while (btf_type_is_modifier(t))
5645 t = btf_type_by_id(btf, t->type);
5646 if (btf_type_is_int(t) || btf_type_is_enum(t)) {
5647 reg->type = SCALAR_VALUE;
5648 continue;
5649 }
5650 if (btf_type_is_ptr(t)) {
5651 if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
5652 reg->type = PTR_TO_CTX;
5653 continue;
5654 }
5655
5656 t = btf_type_skip_modifiers(btf, t->type, NULL);
5657
5658 ref_t = btf_resolve_size(btf, t, ®->mem_size);
5659 if (IS_ERR(ref_t)) {
5660 bpf_log(log,
5661 "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
5662 i, btf_type_str(t), btf_name_by_offset(btf, t->name_off),
5663 PTR_ERR(ref_t));
5664 return -EINVAL;
5665 }
5666
5667 reg->type = PTR_TO_MEM_OR_NULL;
5668 reg->id = ++env->id_gen;
5669
5670 continue;
5671 }
5672 bpf_log(log, "Arg#%d type %s in %s() is not supported yet.\n",
5673 i, btf_kind_str[BTF_INFO_KIND(t->info)], tname);
5674 return -EINVAL;
5675 }
5676 return 0;
5677}
5678
5679static void btf_type_show(const struct btf *btf, u32 type_id, void *obj,
5680 struct btf_show *show)
5681{
5682 const struct btf_type *t = btf_type_by_id(btf, type_id);
5683
5684 show->btf = btf;
5685 memset(&show->state, 0, sizeof(show->state));
5686 memset(&show->obj, 0, sizeof(show->obj));
5687
5688 btf_type_ops(t)->show(btf, t, type_id, obj, 0, show);
5689}
5690
5691static void btf_seq_show(struct btf_show *show, const char *fmt,
5692 va_list args)
5693{
5694 seq_vprintf((struct seq_file *)show->target, fmt, args);
5695}
5696
5697int btf_type_seq_show_flags(const struct btf *btf, u32 type_id,
5698 void *obj, struct seq_file *m, u64 flags)
5699{
5700 struct btf_show sseq;
5701
5702 sseq.target = m;
5703 sseq.showfn = btf_seq_show;
5704 sseq.flags = flags;
5705
5706 btf_type_show(btf, type_id, obj, &sseq);
5707
5708 return sseq.state.status;
5709}
5710
5711void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
5712 struct seq_file *m)
5713{
5714 (void) btf_type_seq_show_flags(btf, type_id, obj, m,
5715 BTF_SHOW_NONAME | BTF_SHOW_COMPACT |
5716 BTF_SHOW_ZERO | BTF_SHOW_UNSAFE);
5717}
5718
5719struct btf_show_snprintf {
5720 struct btf_show show;
5721 int len_left; /* space left in string */
5722 int len; /* length we would have written */
5723};
5724
5725static void btf_snprintf_show(struct btf_show *show, const char *fmt,
5726 va_list args)
5727{
5728 struct btf_show_snprintf *ssnprintf = (struct btf_show_snprintf *)show;
5729 int len;
5730
5731 len = vsnprintf(show->target, ssnprintf->len_left, fmt, args);
5732
5733 if (len < 0) {
5734 ssnprintf->len_left = 0;
5735 ssnprintf->len = len;
5736 } else if (len > ssnprintf->len_left) {
5737 /* no space, drive on to get length we would have written */
5738 ssnprintf->len_left = 0;
5739 ssnprintf->len += len;
5740 } else {
5741 ssnprintf->len_left -= len;
5742 ssnprintf->len += len;
5743 show->target += len;
5744 }
5745}
5746
5747int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
5748 char *buf, int len, u64 flags)
5749{
5750 struct btf_show_snprintf ssnprintf;
5751
5752 ssnprintf.show.target = buf;
5753 ssnprintf.show.flags = flags;
5754 ssnprintf.show.showfn = btf_snprintf_show;
5755 ssnprintf.len_left = len;
5756 ssnprintf.len = 0;
5757
5758 btf_type_show(btf, type_id, obj, (struct btf_show *)&ssnprintf);
5759
5760 /* If we encontered an error, return it. */
5761 if (ssnprintf.show.state.status)
5762 return ssnprintf.show.state.status;
5763
5764 /* Otherwise return length we would have written */
5765 return ssnprintf.len;
5766}
5767
5768#ifdef CONFIG_PROC_FS
5769static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp)
5770{
5771 const struct btf *btf = filp->private_data;
5772
5773 seq_printf(m, "btf_id:\t%u\n", btf->id);
5774}
5775#endif
5776
5777static int btf_release(struct inode *inode, struct file *filp)
5778{
5779 btf_put(filp->private_data);
5780 return 0;
5781}
5782
5783const struct file_operations btf_fops = {
5784#ifdef CONFIG_PROC_FS
5785 .show_fdinfo = bpf_btf_show_fdinfo,
5786#endif
5787 .release = btf_release,
5788};
5789
5790static int __btf_new_fd(struct btf *btf)
5791{
5792 return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
5793}
5794
5795int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr)
5796{
5797 struct btf *btf;
5798 int ret;
5799
5800 btf = btf_parse(make_bpfptr(attr->btf, uattr.is_kernel),
5801 attr->btf_size, attr->btf_log_level,
5802 u64_to_user_ptr(attr->btf_log_buf),
5803 attr->btf_log_size);
5804 if (IS_ERR(btf))
5805 return PTR_ERR(btf);
5806
5807 ret = btf_alloc_id(btf);
5808 if (ret) {
5809 btf_free(btf);
5810 return ret;
5811 }
5812
5813 /*
5814 * The BTF ID is published to the userspace.
5815 * All BTF free must go through call_rcu() from
5816 * now on (i.e. free by calling btf_put()).
5817 */
5818
5819 ret = __btf_new_fd(btf);
5820 if (ret < 0)
5821 btf_put(btf);
5822
5823 return ret;
5824}
5825
5826struct btf *btf_get_by_fd(int fd)
5827{
5828 struct btf *btf;
5829 struct fd f;
5830
5831 f = fdget(fd);
5832
5833 if (!f.file)
5834 return ERR_PTR(-EBADF);
5835
5836 if (f.file->f_op != &btf_fops) {
5837 fdput(f);
5838 return ERR_PTR(-EINVAL);
5839 }
5840
5841 btf = f.file->private_data;
5842 refcount_inc(&btf->refcnt);
5843 fdput(f);
5844
5845 return btf;
5846}
5847
5848int btf_get_info_by_fd(const struct btf *btf,
5849 const union bpf_attr *attr,
5850 union bpf_attr __user *uattr)
5851{
5852 struct bpf_btf_info __user *uinfo;
5853 struct bpf_btf_info info;
5854 u32 info_copy, btf_copy;
5855 void __user *ubtf;
5856 char __user *uname;
5857 u32 uinfo_len, uname_len, name_len;
5858 int ret = 0;
5859
5860 uinfo = u64_to_user_ptr(attr->info.info);
5861 uinfo_len = attr->info.info_len;
5862
5863 info_copy = min_t(u32, uinfo_len, sizeof(info));
5864 memset(&info, 0, sizeof(info));
5865 if (copy_from_user(&info, uinfo, info_copy))
5866 return -EFAULT;
5867
5868 info.id = btf->id;
5869 ubtf = u64_to_user_ptr(info.btf);
5870 btf_copy = min_t(u32, btf->data_size, info.btf_size);
5871 if (copy_to_user(ubtf, btf->data, btf_copy))
5872 return -EFAULT;
5873 info.btf_size = btf->data_size;
5874
5875 info.kernel_btf = btf->kernel_btf;
5876
5877 uname = u64_to_user_ptr(info.name);
5878 uname_len = info.name_len;
5879 if (!uname ^ !uname_len)
5880 return -EINVAL;
5881
5882 name_len = strlen(btf->name);
5883 info.name_len = name_len;
5884
5885 if (uname) {
5886 if (uname_len >= name_len + 1) {
5887 if (copy_to_user(uname, btf->name, name_len + 1))
5888 return -EFAULT;
5889 } else {
5890 char zero = '\0';
5891
5892 if (copy_to_user(uname, btf->name, uname_len - 1))
5893 return -EFAULT;
5894 if (put_user(zero, uname + uname_len - 1))
5895 return -EFAULT;
5896 /* let user-space know about too short buffer */
5897 ret = -ENOSPC;
5898 }
5899 }
5900
5901 if (copy_to_user(uinfo, &info, info_copy) ||
5902 put_user(info_copy, &uattr->info.info_len))
5903 return -EFAULT;
5904
5905 return ret;
5906}
5907
5908int btf_get_fd_by_id(u32 id)
5909{
5910 struct btf *btf;
5911 int fd;
5912
5913 rcu_read_lock();
5914 btf = idr_find(&btf_idr, id);
5915 if (!btf || !refcount_inc_not_zero(&btf->refcnt))
5916 btf = ERR_PTR(-ENOENT);
5917 rcu_read_unlock();
5918
5919 if (IS_ERR(btf))
5920 return PTR_ERR(btf);
5921
5922 fd = __btf_new_fd(btf);
5923 if (fd < 0)
5924 btf_put(btf);
5925
5926 return fd;
5927}
5928
5929u32 btf_obj_id(const struct btf *btf)
5930{
5931 return btf->id;
5932}
5933
5934bool btf_is_kernel(const struct btf *btf)
5935{
5936 return btf->kernel_btf;
5937}
5938
5939bool btf_is_module(const struct btf *btf)
5940{
5941 return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0;
5942}
5943
5944static int btf_id_cmp_func(const void *a, const void *b)
5945{
5946 const int *pa = a, *pb = b;
5947
5948 return *pa - *pb;
5949}
5950
5951bool btf_id_set_contains(const struct btf_id_set *set, u32 id)
5952{
5953 return bsearch(&id, set->ids, set->cnt, sizeof(u32), btf_id_cmp_func) != NULL;
5954}
5955
5956#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
5957struct btf_module {
5958 struct list_head list;
5959 struct module *module;
5960 struct btf *btf;
5961 struct bin_attribute *sysfs_attr;
5962};
5963
5964static LIST_HEAD(btf_modules);
5965static DEFINE_MUTEX(btf_module_mutex);
5966
5967static ssize_t
5968btf_module_read(struct file *file, struct kobject *kobj,
5969 struct bin_attribute *bin_attr,
5970 char *buf, loff_t off, size_t len)
5971{
5972 const struct btf *btf = bin_attr->private;
5973
5974 memcpy(buf, btf->data + off, len);
5975 return len;
5976}
5977
5978static int btf_module_notify(struct notifier_block *nb, unsigned long op,
5979 void *module)
5980{
5981 struct btf_module *btf_mod, *tmp;
5982 struct module *mod = module;
5983 struct btf *btf;
5984 int err = 0;
5985
5986 if (mod->btf_data_size == 0 ||
5987 (op != MODULE_STATE_COMING && op != MODULE_STATE_GOING))
5988 goto out;
5989
5990 switch (op) {
5991 case MODULE_STATE_COMING:
5992 btf_mod = kzalloc(sizeof(*btf_mod), GFP_KERNEL);
5993 if (!btf_mod) {
5994 err = -ENOMEM;
5995 goto out;
5996 }
5997 btf = btf_parse_module(mod->name, mod->btf_data, mod->btf_data_size);
5998 if (IS_ERR(btf)) {
5999 pr_warn("failed to validate module [%s] BTF: %ld\n",
6000 mod->name, PTR_ERR(btf));
6001 kfree(btf_mod);
6002 err = PTR_ERR(btf);
6003 goto out;
6004 }
6005 err = btf_alloc_id(btf);
6006 if (err) {
6007 btf_free(btf);
6008 kfree(btf_mod);
6009 goto out;
6010 }
6011
6012 mutex_lock(&btf_module_mutex);
6013 btf_mod->module = module;
6014 btf_mod->btf = btf;
6015 list_add(&btf_mod->list, &btf_modules);
6016 mutex_unlock(&btf_module_mutex);
6017
6018 if (IS_ENABLED(CONFIG_SYSFS)) {
6019 struct bin_attribute *attr;
6020
6021 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
6022 if (!attr)
6023 goto out;
6024
6025 sysfs_bin_attr_init(attr);
6026 attr->attr.name = btf->name;
6027 attr->attr.mode = 0444;
6028 attr->size = btf->data_size;
6029 attr->private = btf;
6030 attr->read = btf_module_read;
6031
6032 err = sysfs_create_bin_file(btf_kobj, attr);
6033 if (err) {
6034 pr_warn("failed to register module [%s] BTF in sysfs: %d\n",
6035 mod->name, err);
6036 kfree(attr);
6037 err = 0;
6038 goto out;
6039 }
6040
6041 btf_mod->sysfs_attr = attr;
6042 }
6043
6044 break;
6045 case MODULE_STATE_GOING:
6046 mutex_lock(&btf_module_mutex);
6047 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
6048 if (btf_mod->module != module)
6049 continue;
6050
6051 list_del(&btf_mod->list);
6052 if (btf_mod->sysfs_attr)
6053 sysfs_remove_bin_file(btf_kobj, btf_mod->sysfs_attr);
6054 btf_put(btf_mod->btf);
6055 kfree(btf_mod->sysfs_attr);
6056 kfree(btf_mod);
6057 break;
6058 }
6059 mutex_unlock(&btf_module_mutex);
6060 break;
6061 }
6062out:
6063 return notifier_from_errno(err);
6064}
6065
6066static struct notifier_block btf_module_nb = {
6067 .notifier_call = btf_module_notify,
6068};
6069
6070static int __init btf_module_init(void)
6071{
6072 register_module_notifier(&btf_module_nb);
6073 return 0;
6074}
6075
6076fs_initcall(btf_module_init);
6077#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
6078
6079struct module *btf_try_get_module(const struct btf *btf)
6080{
6081 struct module *res = NULL;
6082#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
6083 struct btf_module *btf_mod, *tmp;
6084
6085 mutex_lock(&btf_module_mutex);
6086 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
6087 if (btf_mod->btf != btf)
6088 continue;
6089
6090 if (try_module_get(btf_mod->module))
6091 res = btf_mod->module;
6092
6093 break;
6094 }
6095 mutex_unlock(&btf_module_mutex);
6096#endif
6097
6098 return res;
6099}
6100
6101BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags)
6102{
6103 struct btf *btf;
6104 long ret;
6105
6106 if (flags)
6107 return -EINVAL;
6108
6109 if (name_sz <= 1 || name[name_sz - 1])
6110 return -EINVAL;
6111
6112 btf = bpf_get_btf_vmlinux();
6113 if (IS_ERR(btf))
6114 return PTR_ERR(btf);
6115
6116 ret = btf_find_by_name_kind(btf, name, kind);
6117 /* ret is never zero, since btf_find_by_name_kind returns
6118 * positive btf_id or negative error.
6119 */
6120 if (ret < 0) {
6121 struct btf *mod_btf;
6122 int id;
6123
6124 /* If name is not found in vmlinux's BTF then search in module's BTFs */
6125 spin_lock_bh(&btf_idr_lock);
6126 idr_for_each_entry(&btf_idr, mod_btf, id) {
6127 if (!btf_is_module(mod_btf))
6128 continue;
6129 /* linear search could be slow hence unlock/lock
6130 * the IDR to avoiding holding it for too long
6131 */
6132 btf_get(mod_btf);
6133 spin_unlock_bh(&btf_idr_lock);
6134 ret = btf_find_by_name_kind(mod_btf, name, kind);
6135 if (ret > 0) {
6136 int btf_obj_fd;
6137
6138 btf_obj_fd = __btf_new_fd(mod_btf);
6139 if (btf_obj_fd < 0) {
6140 btf_put(mod_btf);
6141 return btf_obj_fd;
6142 }
6143 return ret | (((u64)btf_obj_fd) << 32);
6144 }
6145 spin_lock_bh(&btf_idr_lock);
6146 btf_put(mod_btf);
6147 }
6148 spin_unlock_bh(&btf_idr_lock);
6149 }
6150 return ret;
6151}
6152
6153const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = {
6154 .func = bpf_btf_find_by_name_kind,
6155 .gpl_only = false,
6156 .ret_type = RET_INTEGER,
6157 .arg1_type = ARG_PTR_TO_MEM,
6158 .arg2_type = ARG_CONST_SIZE,
6159 .arg3_type = ARG_ANYTHING,
6160 .arg4_type = ARG_ANYTHING,
6161};